Could you form an interest group for a national sorority, but make sure the university knows it's a *local* interest group?
I mean, there's ways around things if you want to get creative.
All I can say is, you've got your work cut out for you! From what I've heard, Rio has a rule against everything and if they don't have one, they'll make one quick.
No matter what, though, keep trying--they've got to back down sooner or later! And keep us updated...I'm dying to know how it goes.