WOW! What a complex web you have woven! For my part we are mostly a triad with the occasional other person. For us there really isn't a side taking as one of us always has to be the 'tie breaker' or as we like to call it 'voice of reason'. Almost all of our discussions tend to be out in the open and we actively discourage 'taking sides' though agreeing with someone isn't frowned upon.
Generally we try to avoid making the third person feel like they are in the middle though it is inevitable that it happens. When it does we address the problem quickly and with as little fussing as possible. Beyond that we settle in for a knock down drag out and it seems to draw us closer together rather than driving us apart. There's a skill to disagreeing that can actually leave you feeling better than when you went into the discussion...and we are actively pursuing the perfect scenario. They say practice makes perfect!
I can't imagine getting 8 adults to sit down and discuss problems but I have found that setting aside some regular time (say a monthly meeting) to discuss both the positive and negative goings on. For us we have a bi-weekly set aside night to sit down and talk about whatever has happened in the last two weeks and pay bills, play games, discuss the coming two weeks and what time constraints we might anticipate. Love ain't limited but time sure as hell is!
I wish you all love and luck, sounds like you got a good thing going.