This follows after the Petaybee books by Anne McCaffrey. (Powers That Be, Power Lines, Power Play) It focuses more on the twins than the adults as they grow up. There's a lot of them trying to be more independent, but they also have to figure out who they can trust with their true natures.
I think I'd be hard pressed to find an Anne McCaffrey book that I didn't like and this one is no exception. I love the universes she creates.