diff --git a/render/detailed/summary.go b/render/detailed/summary.go
index 124bbc775..ee00f2d59 100644
--- a/render/detailed/summary.go
+++ b/render/detailed/summary.go
@@ -337,21 +337,21 @@ func weaveNodeSummary(base NodeSummary, n report.Node) (NodeSummary, bool) {
 // groupNodeSummary renders the summary for a group node. n.Topology is
 // expected to be of the form: group:container:hostname
 func groupNodeSummary(base NodeSummary, r report.Report, n report.Node) (NodeSummary, bool) {
-	parts := strings.Split(n.Topology, ":")
-	if len(parts) != 3 {
+	topology, key, ok := render.ParseGroupNodeTopology(n.Topology)
+	if !ok {
 		return NodeSummary{}, false
 	}
 
-	label, ok := n.Latest.Lookup(parts[2])
+	label, ok := n.Latest.Lookup(key)
 	if !ok {
 		return NodeSummary{}, false
 	}
 	base.Label, base.Rank = label, label
 
-	if t, ok := r.Topology(parts[1]); ok {
+	if t, ok := r.Topology(topology); ok {
 		base.Shape = t.GetShape()
 		if t.Label != "" {
-			base.LabelMinor = pluralize(n.Counters, parts[1], t.Label, t.LabelPlural)
+			base.LabelMinor = pluralize(n.Counters, topology, t.Label, t.LabelPlural)
 		}
 	}
 	base.Stack = true
diff --git a/render/id.go b/render/id.go
index 97f5f5b9f..5fa34f8f2 100644
--- a/render/id.go
+++ b/render/id.go
@@ -42,6 +42,15 @@ func MakeGroupNodeTopology(originalTopology, key string) string {
 	return strings.Join([]string{"group", originalTopology, key}, ":")
 }
 
+// ParseGroupNodeTopology returns the parts of a group topology.
+func ParseGroupNodeTopology(topology string) (string, string, bool) {
+	parts := strings.Split(topology, ":")
+	if len(parts) != 3 || parts[0] != "group" {
+		return "", "", false
+	}
+	return parts[1], parts[2], true
+}
+
 // NewDerivedNode makes a node based on node, but with a new ID
 func NewDerivedNode(id string, node report.Node) report.Node {
 	return report.MakeNode(id).WithChildren(node.Children.Add(node))