Usergroups?? on the forums? I don't use them usually it is just a group of people that have higher access rights to something general people don't or a way of separating one group of people from another.
Say I used the forum for two different websites I could separate the people allowing them only to post in areas designed for them...
What was the other thing ummm oh yeah... Linz have you ever looked into downloading "miranda" I believe will work pretty good for your situation at work with im... It is a chat program that you can put on one floppy disk and run it from there when you are done simply take out the disk and you are done.
http://www.miranda-im.org/.. not sure off the top of my head what im's it works for anymore it has been a while since I used it.. But it worked good...