
I don't do hierarchy. I don't know how many times I have to say that to people before it starts to sink in. My partners are human beings with feelings and I have knowingly entered into a relationship where my actions affect them on a deep, intimate level. I cannot possibly prioritize one over another, it would be like prioritizing one parent over another or one child over another. I have to prioritize situations, and I have to consider those situations within the context of our entire relationship and our entire network. There are so many different types of situations and so many variables, that I couldn't possibly even begin to list out anything specific. Everything has to be decided on a case-by-case basis, taking into account everything else in my life.
For example, I might prioritize a live-in partner because we share a daily life so calling to let him know that I won't be home for dinner might be important so that he doesn't waste any effort making dinner for me. But if a long-distance partner comes for a visit, I might spend more time with the long-distance partner than with my local partner because I'll have plenty of time to catch up with the local partner later and the long-distance partner won't have that privilege. But then there are pre-established commitments, like holiday plans or tickets to an event that are already purchased. But then there are one-time-only events or emergencies. And then there are regularly-scheduled events that can afford to be skipped now and then precisely because they're regularly scheduled and something "special" or "important" or "meaningful" might need to take that time slot.
The important part is that every situation gets analyzed both individually and within context, and that every situation gets discussed with all relevant parties. Everyone gets an equal say. Not to each other, no. One of my partners does not get an equal say in what I do with one of my other partners. Everyone I'm in a relationship with is on equal footing to me, not to each other. No one outside of a relationship gets more say about what happens to that relationship than the people in it. That's why priority has to be assigned situationally. I have found that making everyone equal to their own partners in their own relationships yields much better results and more likelihood of everyone being willing to compromise, make sacrifice, and "take turns" with regards to priority because they tend to trust that their turn will come around sometime soon and that it all balances out in the long run. And that fosters far more security, I've found, in relationships than giving any individual top priority all the time, and certainly honors my first commitment far better too.
http://theinnbetween.net/polycommitments.html