I have a rather large assembly of a product we manufacture and lease where I work. I have created an assembly of the entire system out of smaller subassemblies I made from mating together basic parts. The subassembly that is giving me trouble is an arm with pivoting joints at either end that connects the base platform to a bracket on a ring at the top. There are six arms that all connect to the top ring to the base platform in a similar way.

Whenever I attempt to connect more than one arm to both the base and the ring at the top, the components of the mates move out of alignment, breaking mates or causing the system to become overdefined. I have checked that the parts are not fixed, and that the arms have freedom of movement.

My question is: Why do the arms break their mate alignment instead of moving into a position that satisfies all mates? Is there a way I could move them first, rearrange them in hierarchy, or mate them in a different way that wouldn't cause this problem?