diff --git a/gts/gts.csproj b/gts/gts.csproj
index a1619adb..36f1a0aa 100644
--- a/gts/gts.csproj
+++ b/gts/gts.csproj
@@ -3539,6 +3539,7 @@
     <Compile Include="RoomLeaders.aspx.designer.cs">
       <DependentUpon>RoomLeaders.aspx</DependentUpon>
     </Compile>
+    <Compile Include="src\DependencyNode.cs" />
     <Compile Include="src\GamestatsSessionPlat.cs" />
     <Compile Include="src\HeaderColour.cs" />
     <Compile Include="admin\AddDressup.aspx.cs">
@@ -3550,6 +3551,7 @@
     </Compile>
     <Compile Include="src\FakeOpponentGenerator4.cs" />
     <Compile Include="src\OnceTemplate.cs" />
+    <Compile Include="src\RequireLinkBase.cs" />
     <Compile Include="src\RetinaImage.cs" />
     <Compile Include="src\RetinaImageBase.cs" />
     <Compile Include="test\BoxUp.aspx.cs">
diff --git a/gts/src/DependencyNode.cs b/gts/src/DependencyNode.cs
new file mode 100644
index 00000000..8a44733e
--- /dev/null
+++ b/gts/src/DependencyNode.cs
@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Web;
+
+namespace PkmnFoundations.Web
+{
+    public class DependencyNode<TKey, TValue>
+    {
+        public DependencyNode()
+        {
+            Dependencies = new HashSet<TKey>();
+        }
+
+        public DependencyNode(TKey key, TValue value)
+            : this()
+        {
+            Key = key;
+            Value = value;
+        }
+
+        public DependencyNode(TKey key, TValue value, HashSet<TKey> dependencies)
+            : this(key, value)
+        {
+            Dependencies = dependencies;
+        }
+
+        public TKey Key { get; set; }
+        public TValue Value { get; set; }
+        public HashSet<TKey> Dependencies { get; private set; }
+    }
+}
diff --git a/gts/src/RequireLinkBase.cs b/gts/src/RequireLinkBase.cs
new file mode 100644
index 00000000..878ad443
--- /dev/null
+++ b/gts/src/RequireLinkBase.cs
@@ -0,0 +1,168 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Web;
+using System.Web.UI;
+using System.Web.UI.HtmlControls;
+
+namespace PkmnFoundations.Web
+{
+    public abstract class RequireLinkBase : System.Web.UI.Control
+    {
+        protected RequireLinkBase()
+            : base()
+        {
+            this.Init += RequireLinkBase_Init;
+            this.Load += RequireLinkBase_Load;
+            this.PreRender += RequireLinkBase_PreRender;
+        }
+
+        void RequireLinkBase_Init(object sender, EventArgs e)
+        {
+            // todo: only bind once
+            Page.PreRender += Page_PreRender;
+        }
+
+        void RequireLinkBase_Load(object sender, EventArgs e)
+        {
+        }
+
+        void RequireLinkBase_PreRender(object sender, EventArgs e)
+        {
+            DependencyGraph<String, RequireLinkBase> graph = GetDependencyGraph();
+
+            DependencyNode<String, RequireLinkBase> node = new DependencyNode<String, RequireLinkBase>(Key, this, ParseDependencies(After ?? ""));
+            if (!graph.Graph.Any(n => n.Key == Key))
+                graph.Graph.Add(node);
+        }
+
+        void Page_PreRender(object sender, EventArgs e)
+        {
+            DependencyGraph<String, RequireLinkBase> graph = GetDependencyGraph();
+            if (graph.Page == null)
+            {
+                Page.Header.Controls.Add(new RequireLinkRenderer(GetDependencyGraph()));
+                graph.Page = Page;
+            }
+        }
+
+        public String Key { get; set; }
+        public String After { get; set; }
+
+        public abstract void RenderHeader(System.Web.UI.HtmlTextWriter writer);
+
+        /// <summary>
+        /// Obtain a dependency graph which is specific to the Page instance
+        /// and the control class
+        /// </summary>
+        private DependencyGraph<String, RequireLinkBase> GetDependencyGraph()
+        {
+            Type myType = this.GetType();
+
+            Dictionary<Type, DependencyGraph<String, RequireLinkBase>> all_graphs;
+
+            if (!Page.Items.Contains("pkmncfDependencyGraphs"))
+            {
+                all_graphs = new Dictionary<Type, DependencyGraph<String, RequireLinkBase>>();
+                Page.Items.Add("pkmncfDependencyGraphs", all_graphs);
+            }
+            else all_graphs =
+                (Dictionary<Type, DependencyGraph<String, RequireLinkBase>>)Page.Items["pkmncfDependencyGraphs"];
+
+            if (all_graphs.ContainsKey(myType)) return all_graphs[myType];
+
+            DependencyGraph<String, RequireLinkBase> myGraph = new DependencyGraph<String, RequireLinkBase>();
+            all_graphs.Add(myType, myGraph);
+            return myGraph;
+        }
+
+        private HashSet<String> ParseDependencies(String dependencies)
+        {
+            return new HashSet<String>(dependencies.Split(',').Select(s => s.Trim()).Where(s => s.Length > 0));
+        }
+
+    }
+
+    internal class RequireLinkRenderer : System.Web.UI.Control
+    {
+        public RequireLinkRenderer(DependencyGraph<String, RequireLinkBase> graph)
+            : base()
+        {
+            m_graph = graph;
+        }
+
+        private DependencyGraph<String, RequireLinkBase> m_graph;
+
+        protected override void Render(System.Web.UI.HtmlTextWriter writer)
+        {
+            List<RequireLinkBase> links = m_graph.Resolve();
+
+            foreach (RequireLinkBase link in links)
+                link.RenderHeader(writer);
+        }
+    }
+
+    internal class DependencyGraph<TKey, TValue>
+    {
+        public DependencyGraph()
+        {
+            Graph = new List<DependencyNode<TKey, TValue>>();
+        }
+
+        public DependencyGraph(List<DependencyNode<TKey, TValue>> graph)
+        {
+            Graph = graph;
+        }
+
+        public List<DependencyNode<TKey, TValue>> Graph;
+        public Page Page = null;
+
+        public List<TValue> Resolve()
+        {
+            // fixme: we should clone the DependencyNodes so they don't get modified.
+            LinkedList<DependencyNode<TKey, TValue>> nodesList = new LinkedList<DependencyNode<TKey, TValue>>(Graph);
+            List<TValue> result = new List<TValue>(nodesList.Count);
+
+            while (nodesList.Count > 0)
+            {
+                LinkedListNode<DependencyNode<TKey, TValue>> nodeLinked = nodesList.First;
+
+                while (nodeLinked != null)
+                {
+                    if (nodeLinked.Value.Dependencies.Count == 0) break;
+                    nodeLinked = nodeLinked.Next;
+                }
+
+                if (nodeLinked == null)
+                {
+                    // we hit the end of the list without finding a dependency-less node.
+                    // this means there has to be a circular dependency.
+                    // ie. every remaining node in the list depends on some other remaining
+                    // node in the list.
+
+                    // todo: display the actual cycle (or an example if there's more than one)
+                    // in this exception.
+                    // algo:
+                    // Keep a collection of found nodes.
+                    // Start at the first node, adding it to the collection.
+                    // Move to the node of the first dependency of this node and add it to the collection.
+                    // Repeat until you reach a node which is already in the collection.
+                    // Output the collection of nodes, starting at the node which was already found.
+                    throw new Exception("Circular dependency found in your links.\n" +
+                        "Keys:\n" +
+                        String.Join("\n", nodesList.Select(n => n.Key).ToArray()));
+                }
+
+                // add this node to output, remove it as a dependency from the remaining nodes
+                DependencyNode<TKey, TValue> nodeOutput = nodeLinked.Value;
+                nodesList.Remove(nodeLinked);
+
+                foreach (DependencyNode<TKey, TValue> nodeValue in nodesList)
+                    nodeValue.Dependencies.Remove(nodeOutput.Key);
+
+                result.Add(nodeOutput.Value);
+            }
+            return result;
+        }
+    }
+}