It started as a way to bring three generations of family, spread across the globe, under one roof. Expertly sited on a two-and-a-half acre lot with private waterfront access, a 7,200-square-foot residence in Water Mill, New York, serves as home base for five adults and five preteens for summers, weekends, and holidays. “The challenge was making a viable whole for a family with disparate interests and age groups,” says architect Andrew Berman.