“Ms. Siegal, 68, has employed sharp elbows and inexhaustible energy reservoirs to claim a unique social position in New York and the Hamptons: as a host for hire for clubby, insider-only film screenings and dinners for the influential, she stands at the crossroads of Hollywood power and New York society (or what’s left of it), functioning as a spin doctor, salonista, celebrity confidante and, occasionally, bouncer.”