Note my screenshot - what I'm trying to accomplish is that when any of the outer "arms" move, the center, vertical bone moves along with it, basically in an IK relationship - tilting based on the moving arm. However, I'm only aware of how to do any IK stuff by using parental relationships. Since bones can only have one parent, I'm not sure how to accomplish what I wanted.
I tried adding multiple "Copy Transform" constraints from the arm bones to the center bone, but it seems like the constraints just execute in order and whichever one is last overwrites the others.