diff --git a/packages/devtools/src/__tests__/signal-resources.test.ts b/packages/devtools/src/__tests__/signal-resources.test.ts
index 6fbcccd8..b1693105 100644
--- a/packages/devtools/src/__tests__/signal-resources.test.ts
+++ b/packages/devtools/src/__tests__/signal-resources.test.ts
@@ -46,6 +46,30 @@ describe('groupResources', () => {
     ]);
   });
 
+  it('keeps an unnamed resource whose params read another unnamed resource apart from it', () => {
+    const nodes = [
+      node('1', 'computed', 'Resource.value', 'Ada'),
+      node('2', 'linkedSignal', 'Resource.state'),
+      node('3', 'linkedSignal', 'Resource.extRequest'),
+      node('4', 'computed', 'Resource.value', ['Ada post']),
+      node('5', 'linkedSignal', 'Resource.state'),
+      node('6', 'linkedSignal', 'Resource.extRequest'),
+    ];
+    const edges: SignalGraphEdge[] = [
+      { consumer: 0, producer: 1 },
+      { consumer: 1, producer: 2 },
+      { consumer: 3, producer: 4 },
+      { consumer: 4, producer: 5 },
+      // The second resource's params read the first resource's value.
+      { consumer: 5, producer: 0 },
+    ];
+    const resources = groupResources(nodes, edges, [], serialize);
+    expect(resources.map((r) => [r.name, r.value, r.nodeIds])).toEqual([
+      ['resource 1', 'Ada', ['1', '2', '3']],
+      ['resource 2', ['Ada post'], ['4', '5', '6']],
+    ]);
+  });
+
   it('derives status from the graph when no instance holds the resource', () => {
     const nodes = [
       node('1', 'computed', 'Resource#trips.value', '(threw an error)'),
diff --git a/packages/devtools/src/signal-resources.ts b/packages/devtools/src/signal-resources.ts
index 65d91e88..59035e39 100644
--- a/packages/devtools/src/signal-resources.ts
+++ b/packages/devtools/src/signal-resources.ts
@@ -115,7 +115,8 @@ function groupsOf(nodes: SignalGraphNode[], edges: SignalGraphEdge[]): Group[] {
     if (!valid(e)) continue;
     const a = parsed[e.consumer];
     const b = parsed[e.producer];
-    if (a && b && a.name === b.name) union(e.consumer, e.producer);
+    // extRequest reads the user's params, which may read another resource.
+    if (a && b && a.name === b.name && a.part !== 'extRequest') union(e.consumer, e.producer);
   }
   // httpResource signals have plain names: `_statusCode` and friends read the
   // resource's own signals, and its `stream` is read by the resource value.