Sorority, witchcraft film from early 1980s [solved]

Anyone recall this movie?

Two stepsisters go off to the same college. The glamorous spoiled sister gets into her Mom's sorority of rich party girls who date the guys from the rich boy frats. The stepsister doesn't get into this sorority but joins an outcast sorority. The glamorous sister cares about her stepsister and tries to stop her from pledging with the outcasts. The stepsister also has superpowers of some sort, kind of like Carrie. I forget what happens but tensions rise and there is a Carrie-like superpower revenge moment. Some mean girls from the popular sorority perish in ugly ways. I think the stepsister dies too, and the film ends with the glamorous sister joining the outcast sorority. There may have been a shared love interest dude too.