You may want to look into Beta Sigma Phi sorority. Although it is a community sorority, it does have some college-only chapters. For example:
http://www.kettering.edu/~betasigb/
Other community sororities may also have college-only chapters, but you would have to contact them.
List of community organizations compiled by BetaRose can be found in the GC thread:
http://www.greekchat.com/gcforums/an...ment.php?f=208
Also info on community sororities:
http://www.communitysororities.org
Hope this helps - good luck!