That one line is all you need. Put it in the admin and mod hooks for showgroups and you are all set. Now, if you want the user's location, that takes a little more code in 3.7.0. They chopped some stuff out of the showgroups file. I'm still trying to fiogure out a way to get the Usergroup descriptions in there. The code I used to use isn't in showgroups.php anymore.
Yes, they use $user all through there. I figured you would have caught that with all the stuff you have done with it, but it can get frustrating when something doesn't work. You get to the point you will try almost anything. Been there, still doing that.