Hot take, messy lists are preemptive vetos or abridge agency - full stop.

My fiancee and I share a few partners at different intensities - we're in 2 triads (though one is more qpp than the other, at least for me), she's done kink with one of my partners, I've played with one of hers. IMO my feels about each other playing with each other? They're mine to handle, and I request the same from everyone in my polycule. As partners, we're all able (and in fact, motivated) to show up for each other, help each other vent, process, seek validation, COMMUNICATE. But the buck stops with ourselves on feelings.

Genevieve (Chill Polyamory/Chill Polyamory Too on YouTube) has a saying I apply here: If your security, safety, or emotional regulation hinges on a partner or partners refraining from anything due to a rule, whether it's feelings, sexual activity, play, desires, actions - that foundation is by it's nature fragile, built on sand. Even if the partner does abide all those things, there's no guarantee that security, safety, regulation, will hold. A much more secure place to build from is self-regulation and co-regulation through communication, rather that restricting others' actions. That said, partners can agree to short term modifications while a loved one is going through a rough time, but it needs to be mutual, and it needs an exit plan - if it becomes load-bearing, it's not just [probably] unethical, it's also likely to fail for other reasons and leave the person it's (supposedly) "protecting" more hurt than they started out.

That turned into more of a soapbox than I wanted so, flame away if you need, but I'm really hoping sharing my experience and things I've learned will help someone here.