diff --git a/lib/user.js b/lib/user.js
index <HASH>..<HASH> 100644
--- a/lib/user.js
+++ b/lib/user.js
@@ -106,7 +106,14 @@ module.exports = {
   denyTracking: function(){
     refs.userMeta.child('trackOk').set( false );
   },
+
+  /*
+   * Group Support
+   */
   setGroup: function(key, devices) {
+    if (devices === null) { // Just create group without any device.
+      refs.userGroups.child(key).set(false);
+    }
     refs.userGroups.child(key).set(devices);
   },
   deleteGroup: function(key) {
ability to create a group without devices.