I think I've encountered the a similar problem (so I think) with families and containers.
I have families A,B,C and D and want to always set the positions of B,C and D to the position of A. Objects of the from families A,B,C and D are always grouped in a container.
When I first tried this objects from different containers were positioned together in a mixed up manner (however still one object of family A,B,C and D each).
However changing the Z order seems to solve this problem. I just made sure that objects in the same container are directly subsequent to another.
It's a bit of a hack, but it could help people who have similar problems to the one I had.
Families and containers have difficulties with one another.
(I'd still like an object that could have other objects as private variables...)