I'm looking for stories where at least one of the main characters is the child of a group marriage—that is, was raised in a household where more than two adults in a mutual relationship had parental responsibility for the character. It's okay if the parentals are also main characters, but I'm interested in the next generation and how that environment shaped them.
One example: Kate in aroslov's Model Student series, raised on a free-love commune. Any others?
TIA