How to bold one usergroup? To make one primary?

[cookiepants]

I have 133 members that purchased a sponsorship in the past year. We upgraded the boards recently and I went in and edited the paid sponsorship user group information.

They are still showing up as Registered users as their primary user group and Sponsors as a secondary group.

I see I can go in and change it sponsor by sponsor so they are only in the sponsorship user group.

Is there a way to do this in a mass way?

If I were to create a new user group, with all the correct permissions that I want, can I then promote the sponsor group to the new group I create? Or will that mess things up more?

I want to be able to identify the paid sponsors of the site, but as I'm finding this is becoming troublesome.

--------------- Added at 15:29 ---------------

you can go to my site here:
http://www.sewingmamas.com/b/

and log in:
trailrun

password:
password