Alternate account for specific forums

[retrofade]

On my board, we have some users playing a D&D game in a specific forum setup for that purpose. I was wondering if it might be possible to set the forum up in such a way so that when specified users posted in that forum, it would show them as a different "account" or alter-ego of their choosing with a different avatar than their standard one as well.

I know this can be done by just having them register with that username and set their access to only be able to post in that forum....but I don't really want to have to do that.

I hope I made some sense...if not, let me know and I'll try to explain it better.