I absolutely have great friends from other sororities! It's what made my college experience so special.
My two best friends are DDD and DG. I have a close knit group of friends from other sororities, who I have had no problem maintaining friendships after college. I was lucky enough to be able to meet a lot of girls working on various events. This is not to imply that I am not incredibly close with my sorority sisters though.
Carrie