I have a pretty basic model made up of 4 different parts, its a 2d replication/view of a 3d model to simplify things a bit and it's used to help work out a few calculations and values for each part in relation to others. One of these parts revolves/rotates around a single point. Only issue is, that, this single point moves as the part rotates (as other parts move, which effect where the rotation point is).

At the moment, I have a simple cylinder/circle axis mate where the part rotates about, but, this isn't as accurate as the moving rotation point. Is it possible to make a rotation point for a part in the assembly that's based on where 3 centre lines meet/cross over, which moves as the parts are moved.