Force new registrations to choose usergroup?

[AFemaleProdigy]

I am trying to figure out how to force new users registering to choose the usergroup they would like to be in. I can't find anything that works with vb4 and have asked about it in several other places, but no one is answering. Is there an available plugin or can someone tell me what code changes to make to do it myself?

By default, vB places the user into the appropriate group (coppa or registered). I want users to have specific groups to choose from when they are signing up. I want them to be required to choose their usergroup. Example: I might have 10 different group IDs, but only want them to be able to choose a specific set of 4 usergroups (12,18,20,28), how would I do that?