Herm, I say go for it! What do you have to lose? OnePlus69Is70 gave some good advice in suggesting you speak with somebody in the Student Life office.
I echo what ChiOJenn78 says though. UST is pretty religious, so I do not know if they will embrace the idea of Greek life, but that should not keep you from trying. Who knows. I may be at St. Thomas to help get things rolling.
(Back-up only)