On a ceaselessly rainy day this month, the residents of the Whitby gathered inside the lobby of the grand old building in Manhattan for its annual Christmas party. Children crawled and darted around the legs of clustered parents. Plastic folding tables were laden with nuts, cold cuts and pizza. Soda and wine sloshed in disposable cups while the lights and ornaments twinkled on a small artificial Christmas tree.

Conversation turned predictably to children and work, as well as to the shows people had seen. More often than not, these were one and the same.

“I’ll be out on a job and see someone I think I recognize from a past gig,” said Paul Ford, a rehearsal pianist and frequent Stephen Sondheim collaborator who has lived at the Whitby since 1983. “We’ll get to talking, and it turns out I know them from the elevator.”