Hi! check out my scene file. I created a procedural way of do some parent/child relationships between pieces(prims) at sop level, and also per prim transformations of course. You'll be able to create your own rules for the transformation point position, transform operations and hierarchies description. Here is the link and a Video in which I tried to explain some of the features that it has, pardon my poor english and have fun!
Scene File: https://gum.co/polyops
Good Luck!