Heavenly Desire (1979)

In 1879 Wild West California, prostitute Mary Lou and her friend Rosebud are accidentally gunned down after witnessing the death of Mary Lou's dim-witted lover Ralph. 100 years later, the Devil recruits the limbo-state souls of Mary Lou and Rosebud to return to their brothel, now a Los Angeles college sorority, to try to bring two newcomers to the place, Ellen and Sue, to make them lose their virginity to their boyfriends in order for them to gain access into swinging Hell.