Psycho Sisters (1994)

Jane and Jackie are driven far beyond the brink of madness after witnessing the brutal rape and murder of their younger sister by a group of marauding college fraternity brothers. Upon the release from an insane asylum, the sisters embark on a relentless search for the guys that raped and strangled their sister. Obsessed with revenge and fueled by a hatred of all men, they kill any man that crosses their path, retaining his severed genitals as a trophy.