Nightmare Sisters

The name of this movie is Nightmare Sisters released in 1988-06-15 and it's main theme is Melody, Marci, and Mickey are three geeky college girls who can't get a date. One night, they invite some geeky college guys over and have a seance that results in the girls becoming possessed and turning into sex starved vamps. Will the geek hero guys be able to stop the horrible ? possession?.