Did you mention something about getting in touch with local alumnae groups? If you have local alum groups, then you have alums!

Do you have a Panhellenic Alum Assoc in your area? That is a very good place to get in touch with alums in your area. Go to the national panhellenic website and do a search for a group in your area. Also, if you know older girls from your town who were in sororities in college, they may be able to tell you who wrote recs for them.
Don't give up!