The High School War — Francine Pascal

Sweet Valley High and rival Palisades High are caught in a full-fledged war with Jessica Wakefield in the middle. She's fallen in love with a rival from Palisades. What will her boyfriend, Ken Matthews, do when he finds out? Her twin, Elizabeth Wakefield, has troubles of her own. What will her boyfriend, Todd Wilkins, do when he finds out that Elizabeth is the one who called the police during a school dance disturbance that resulted in his being arrested?