multiple compositions

Hello, I have this composition I've been working for some weeks, and it has a problem that I just can't find a way to solve. I'm going to try to explain it as simply as possible. I'm using 2 (equal) displays connected to a Mini Mac (one through the mini port, the other through the hdmi). In one display I show some AR (6 six different markers) output, and in the other one I show information about the respective activated marker. The composition is going to a museum so it has to be running all the time. Because of that, I'm using QC Builder so I can "autorun" the application generated. The problem is that I don't know how to make it span the 2 displays. I thought about splitting the composition in two and run one in display 1(the AR result) ,the other in display 2(the additional info) and make one communicate/activate the other, but I have no idea how to "link" two separate compositions (or even if this makes any sense at all :)

Can anybody help?Is there any other well known alternative?

Thanks in advance