Sure: the SCOTUS has decreed there is a right to marry. Therefore you cannot legally prevent anyone from doing so. Polygamy? On what grounds do you stop it?
Can a group of people form a marriage co-op? Do not see why not.
It doesn’t have to be based on sex. It could be monetary. A father could marry his son so as to avoid inheritance taxes. The son gets spousal benefits.
Marriage has no meaning. It was destroyed by the few words of heathens.
Correct me if I’m wrong, but I heard that, in the states that passed “same-sex marriage,” you could not marry unless there was an intimate relationship of some kind involved. IOW, two straight friends “marrying” for financial reasons, for example, might be investigated.
It sounded similar to the way people are investigated for “green card marriages” - marrying so one person can stay in the country and then divorcing soon afterward.