First aid kit when friends are in conflict

Conflict is a growth industry for mediators like myself. It's sad that I can say it's a growth industry! I would love to work myself out of a job. Yet the growth of conflict is, in my view, directly proportional to the growth in stress caused by many issues.
But what do you do when friends get into conflict with a high potential to ruin their relationship? What do you say to them?
I have a couple of friends who have been building critical mass in their relationship for years. The fuze has lately been lit! Ultimatums and demands have been made and emotional walls that were already under construction have been finished and fortified, and the parties are in the process of enlisting their friends. This is natural. We go to our trusted friends for support. Yet, what we, as the friend must remember, is that we aren't getting both sides of the story. We are getting one person's "truth" which will look significantly different than the "truth" the other person is telling. Whose side do we choose? Logically we would say: "I want to remain neutral," but if one of the parties has approached us or if we like one of them better we will subconsciously weigh in on their side.
Conflict is a contagious disease. If we are recruited (which we may not realize that we've been recruited) we react to the stress of the conflict by sharing it with someone we love. In a way, we are recruiting them into the fray! The disease can infect our personal relationship with our loved one very easily.

When I am mediating conflict I ask both parties to share (briefly) their story. Then I tell them that the past is non-negotiable because it can not be changed. We can, at best, hope to survive the present and negotiate an agreement to settle the conflict. An agreement does not assign blame, it does not pick a side, it does not make judgements. It simply creates a future condition that the parties agree will manage their relationship.

I'm trying to remain neutral in the conflict my friends are in. I definitely do not have both sides of the story and what I do know I've gathered from my historic interaction with them and what I've been told second hand. So, how will I survive their conflict? How will I prevent their conflict from infecting my relationship with my partner? I told my partner that I wanted to remain as neutral as I could be. I said I didn't have enough facts to weigh in, and I told her that the "facts" she was getting were heavily weighed and one-sided. I was careful to explain enlistment, "absolute truth" and other conflict traps. Then I told her that I saw my role as that of a listener, not for my friends but of her. If our friend's conflict was hurting my partner I promised I would listen to Her Fears, that I would hold her close, that I would gently but firmly not pick sides, and that the only relationship I would work hard to save would be ours.