Caught in the middle

I try to stay out of it.  By that I mean I try to stay out of political battles at work.  If two partners want to fight over my valuable time - then it's between them.  I just do what I am told.  The last place I want to be is caught in the middle of two people trying to assert their so called political power.

Generally speaking I do 95% of my work for one partner, with the occasional project (say three times a year) for the head of my practice group.  And then there is the occasional project that I get asked to do, where someone has to tell the other partner no, or I get told I have to do it.  The hard part is when partner B, the one that I don't work for, comes to me directly requesting my time.  I immediately involve partner A, the partner that I work for, because ultimately it should be up to him if he wants to give my time away.  And like I said, it goes one of two ways.  Partner A will either stick up for himself/me, or he will be beaten out by partner B.

Well this time I am caught right smack in the middle of three partners.  They all want something different. They all have competing interests.  And I already have the work load of 2-3 people.  I can't be three places at once.  It is simply not possible for all three partners to get what they want.

So partner B came to me assuming that I was going to drop all of partner A's work to do this project that is totally unrelated to the kind of law I practice.  I went immediately to partner A and partner A and I had a conversation in which I told him the truth about how I feel about doing the project (yay me for sticking up for myself), and we agreed that I don't have time to do the project and that we should gracefully say no.  Wait, he said I should say no.  What?  All of a sudden I am finding myself having to tell a partner no, when I strongly think that this is the other partner's responsibility.  It puts me in a really awkward position.  I feel like I am being sent in to do the dirty work and it is making me really uncomfortable.  

This is what is going to happen.  I am going to tell partner B no (tomorrow - eek).  Partner B is going to go tell partner C that I said no.  Partner C is going to go to partner A (the one that I work for), and partner A is going to have to stick up for the both of us, otherwise I am going to get screwed into doing partner B's project because partner C has his own selfish agenda.  I see myself getting screwed in this situation.  First of all, I am terrified to say no - but the reality is, unless we pull me off of my entire work load, I can't do the project.  It's about a 3-4 month deal project that would take all my time.  For one thing I hate deals.  There is a reason why everything I do is regulatory compliance related.  And also, I know nothing about the substance of this deal, or doing a deal at all for that matter.

I don't really know quite what to do honestly.  I just have to hope that the person I work for is willing to fight this one out.