
Polygamous is one married to more while polyamory is the act of having intimate relationships with more than one person at the same time but to answer your question. Nope. There can be one dominant and alot of submissive or vice versa or balance like. It depends on what the couples want if they set some rules.

Are you confusing threesomes + group sex (solely sex-fueled) with poly relationships? (feel free to correct me, this is what I'm getting from your comment) Because those can be to spice up a relationship and would be considered an open relationship. Poly relationships on the other hand is closed and everyone loves (in the romantic sense) each other and feel comfortable. Poly relationships really just work the same as mono relationships, where you love and respect the other partner(s). Just as how every relationship varies, so do theirs, the only difference is the number of ppl involved. Hope this helped ٩(๑❛ᴗ❛๑)۶
so in every polygamous (is that what u call it?) relationships, is there really a need for someone to be a switch (like can be both top and bottom)?? also, some facts on polygamous relationship is also helpful :3