How to bulk add users to User Management after upgrade

Everything is current, all modules are renewed. I think the major issue for me is, it says it created an “All Users” group by default, and I thought by default everyone was part of that group, but that doesn’t seem to be the case. I am guessing as this was an upgraded PBX, it didn’t automatically bring everyone into the default group.

If I am right on that guess, then the million dollar question is, how can I drag all 600 extensions into the default group, so everyone has UCP voice mail access by default. At the moment it looks like I have to run in though the User Management module, and add each user one at a time, and with that many extensions, it’s sure going to be a long tedious process. So hopefully there is some way to do this en mass.