Can I allow users to add themselves to certain change usergroups? i.e liverpool fans

[cowcowcow]

The Idea:

Lets say i have a football website (i dont really but this is easiest analogy). I want users to be able to choose their favourite club. They can choose to be liverpool, man utd, or both. Once they choose liverpool their usergroup, they can see only the latest liverpool news, and vice versa with man utd. if they choose all they can see all news.

I know how to give them the permissions to see/hide this by editing the usergroups permissions and i guess the html for style options would be something like this

if (is_member_of($vbulletin->userinfo, 1)) $styleid = x;

but what i do not know how to do is

Q: Can you give users the option to be add/remove themselves from specific usergroups?

Like a simple tickbox to change their usergroup. Meaning you specify certain usergroups the user can choose to be part of which has same permissions as registered users just different display options so their screen is not so cluttered. And this is all automated by themselves and you dont have to move them manually or wait for the usergroup promotion scheduler to run.

Any help would be much appreciated, thanks!