Parent Trap III (1989)

Triplets Megan (Joy Creel), Lisa (Leanna Creel), and Jessie (Monica Lacy) have all returned from their summer vacations to discover that their father Jeffrey Wyatt (Barry Bostwick) is getting married to snob Cassie McGuire (Patricia Richardson). When Cassie hires decorator Susan Evers (Hayley Mills) to redecorate their house, the triplets believe Susan is the right woman for their father. The planning begins.