user select usergroup at signup

[JJH35]

Im not sure if this is possible without a hack/mod whatever from vbulletin.org (if it is could someone please provided the mod URL)

Anyway, is it possible to on the signup page (because I am planning to breakdown a forum into completely different subjects/areas) to have the user select their usergroup limited to the usergroups i provide them to chose from? Im looking for something automatic, rather than them filling in a text box and me seeing their answer and manually moving them there.

Hope this makes sense, if not ill try to reword it