[astroAPhi]

If you want to get anywhere, you have to try. Go to your director of Student Affairs and tell him or her that you are interested in starting a sorority on campus. Give reasons why you think there needs to be one on your campus. Ask that at the very least, you'd like to start a women's social club. In that case, you might not be able to use Greek letters, but you could still form a "sisterhood" from that.

If you want to start a sorority, you will definitely need the school's blessing, and it won't be a decision that is reached quickly. I'm betting it would take you at least a year to convince the administration that you need a Greek system (or even just one organization!). I'd start forming a good arguement, because you're going to get grilled.