[Lawtonfogle]

Perhaps simpler would be allowing one person to be in multiple 2 person marriages at once. Even if one of these must be set as the primary, for which all tax benefits, etc. apply to. So while a 3 person marriage would leave one person with no primary, a 4 person marriage would really be 6 marriages, only 2 of which are primary and which function mostly the same. Any special cases like power of attorney could work through the primary marriage unless a legal document was drafted that changed the functionality.

I'm sure a think tank can form a much better option than the one I crafted in under 5 minutes.