GROUP !?

The new and undocumented group command gives me a little headache. I have recieve a drawing wit something like 100+ unnamed groups in it.Now I want to ungroup app 20 specific groups.The only way to do this seems to be through the group dialog. The problem is how to choose the right groups. As far as I can see the only way to know is to pick one group in the list and ask for it to be highlighted. OOPS wrong one back and try next , and so on.....This can also only be performed on one group at a time. I would of course like to pick a number of groups on in the drawing then invoke the group command and do what I want with them.