diff --git a/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.cpp b/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.cpp
index 5305f7f8667..bc520ae8e9c 100644
--- a/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.cpp
+++ b/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.cpp
@@ -10,7 +10,6 @@
 #include <AutoLocker.h>
 
 #include "LocalTargetHostInterfaceInfo.h"
-#include "TargetHostInterface.h"
 #include "TargetHostInterfaceInfo.h"
 
 
@@ -20,7 +19,9 @@
 
 TargetHostInterfaceRoster::TargetHostInterfaceRoster()
 	:
+	TargetHostInterface::Listener(),
 	fLock(),
+	fRunningTeamDebuggers(0),
 	fInterfaceInfos(20, false),
 	fActiveInterfaces(20, false)
 {
@@ -136,6 +137,7 @@ TargetHostInterfaceRoster::CreateInterface(TargetHostInterfaceInfo* info,
 		return B_NO_MEMORY;
 	}
 
+	interface->AddListener(this);
 	_interface = interface;
 	return B_OK;
 }
@@ -155,14 +157,24 @@ TargetHostInterfaceRoster::ActiveInterfaceAt(int32 index) const
 }
 
 
-int32
-TargetHostInterfaceRoster::CountRunningTeamDebuggers() const
+void
+TargetHostInterfaceRoster::TeamDebuggerStarted(TeamDebugger* debugger)
 {
-	int32 total = 0;
-	for (int32 i = 0; TargetHostInterface* interface = ActiveInterfaceAt(i);
-		i++) {
-		total += interface->CountTeamDebuggers();
-	}
+	fRunningTeamDebuggers++;
+}
+
+
+void
+TargetHostInterfaceRoster::TeamDebuggerQuit(TeamDebugger* debugger)
+{
+	fRunningTeamDebuggers--;
+}
+
 
-	return total;
+void
+TargetHostInterfaceRoster::TargetHostInterfaceQuit(
+	TargetHostInterface* interface)
+{
+	AutoLocker<TargetHostInterfaceRoster> locker(this);
+	fActiveInterfaces.RemoveItem(interface);
 }
diff --git a/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.h b/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.h
index d09ff9b2426..9016aa457c3 100644
--- a/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.h
+++ b/src/apps/debugger/target_host_interface/TargetHostInterfaceRoster.h
@@ -10,13 +10,14 @@
 #include <Locker.h>
 #include <ObjectList.h>
 
+#include "TargetHostInterface.h"
+
 
 class Settings;
-class TargetHostInterface;
 class TargetHostInterfaceInfo;
 
 
-class TargetHostInterfaceRoster {
+class TargetHostInterfaceRoster : private TargetHostInterface::Listener {
 public:
 								TargetHostInterfaceRoster();
 	virtual						~TargetHostInterfaceRoster();
@@ -42,7 +43,14 @@ class TargetHostInterfaceRoster {
 			int32				CountActiveInterfaces() const;
 			TargetHostInterface* ActiveInterfaceAt(int32 index) const;
 
-			int32				CountRunningTeamDebuggers() const;
+			int32				CountRunningTeamDebuggers() const
+									{ return fRunningTeamDebuggers; }
+
+	// TargetHostInterface::Listener
+	virtual	void				TeamDebuggerStarted(TeamDebugger* debugger);
+	virtual	void 				TeamDebuggerQuit(TeamDebugger* debugger);
+	virtual	void				TargetHostInterfaceQuit(
+									TargetHostInterface* interface);
 
 private:
 			typedef BObjectList<TargetHostInterfaceInfo> InfoList;
@@ -52,6 +60,7 @@ class TargetHostInterfaceRoster {
 			BLocker				fLock;
 	static	TargetHostInterfaceRoster* sDefaultInstance;
 
+			int32				fRunningTeamDebuggers;
 			InfoList			fInterfaceInfos;
 			InterfaceList		fActiveInterfaces;
 };