diff --git a/confluent_server/confluent/config/configmanager.py b/confluent_server/confluent/config/configmanager.py
index 4ccedf99..c165278a 100644
--- a/confluent_server/confluent/config/configmanager.py
+++ b/confluent_server/confluent/config/configmanager.py
@@ -2023,7 +2023,11 @@ class ConfigManager(object):
                 continue  # next node, this node already in
             self._node_added_to_group(node, group, changeset)
 
-    async def add_group_attributes(self, attribmap):
+    async def add_group_attributes(self, attribmap, checkconflict=False):
+        if checkconflict:
+            for groupname in attribmap:
+                if groupname in self._cfgstore.get('nodes', {}):
+                    raise ValueError('Group "{}" conflicts with an existing node'.format(groupname))
         await self.set_group_attributes(attribmap, autocreate=True)
 
     async def set_group_attributes(self, attribmap, autocreate=False, merge="replace", keydata=None, skipped=None):
@@ -2422,7 +2426,11 @@ class ConfigManager(object):
         self._notif_attribwatchers(changeset)
         self._bg_sync_to_file()
 
-    async def add_node_attributes(self, attribmap):
+    async def add_node_attributes(self, attribmap, checkconflict=False):
+        if checkconflict:
+            for nodename in attribmap:
+                if nodename in self._cfgstore.get('nodegroups', {}):
+                    raise ValueError('Node "{}" conflicts with an existing group'.format(nodename))
         await self.set_node_attributes(attribmap, autocreate=True)
 
     async def rename_nodes(self, renamemap):
diff --git a/confluent_server/confluent/core.py b/confluent_server/confluent/core.py
index 82da37f7..29073c88 100644
--- a/confluent_server/confluent/core.py
+++ b/confluent_server/confluent/core.py
@@ -818,7 +818,7 @@ async def create_group(inputdata, configmanager):
     except KeyError:
         raise exc.InvalidArgumentException()
     try:
-        await configmanager.add_group_attributes(attribmap)
+        await configmanager.add_group_attributes(attribmap, checkconflict=True)
     except ValueError as e:
         raise exc.InvalidArgumentException(str(e))
     yield msg.CreatedResource(groupname)
@@ -834,7 +834,7 @@ async def create_node(inputdata, configmanager):
     except KeyError:
         raise exc.InvalidArgumentException('name not specified')
     try:
-        await configmanager.add_node_attributes(attribmap)
+        await configmanager.add_node_attributes(attribmap, checkconflict=True)
     except ValueError as e:
         raise exc.InvalidArgumentException(str(e))
     yield msg.CreatedResource(nodename)
@@ -850,7 +850,7 @@ async def create_noderange(inputdata, configmanager):
     except KeyError:
         raise exc.InvalidArgumentException('name not specified')
     try:
-        await configmanager.add_node_attributes(attribmap)
+        await configmanager.add_node_attributes(attribmap, checkconflict=True)
     except ValueError as e:
         raise exc.InvalidArgumentException(str(e))
     for node in attribmap: