I don't remember having a rivalry with a particular sorority. I do remember one sister of a sorority hating me because I was friends with her boyfriend. I knew him for three years before they started dating. Anyway, I was friends with more than half of her sisters, and she started talking sh*t about me to her sisters. They thought that she was nuts because they knew me. It made her look really bad.
As for the guys, when alcohol and testosterone mix it is a recipe for beer muscles and big fights. I never saw any fights in person, but I remember seeing one guy with a broken nose. Ouch!