By assigning the last hip row to the abdomen it is possible to make the hip disappear completely
I tried that initially but was having difficulty with the dreadful group editor, but I'll try it again.
The way I described above, just changing some of the hip to an invisible material should have the same effect.
I don't know how it would be possible to record and assign a change of the faces and which bones are visible
It is possible for script to log all that. And then reproduce it again.
I was explaining it above only without referring to the Poser Python methods that do it.
It takes a few methods to collect all that, and some data structures.
I've done a very similar thing already so there are chunks of code called 'functions' that I have made and stored away in my python library which can be reused for this.
So it's kind of like putting together modules.
Well, have faith. I'm pretty sure about this, so hang in there 'till I can make a test version.
I'm having fun with it anyway, and can go further without needing your geometry, but it might help.
I made some test geometry that is so stupid looking that I had to laugh. But, I apologized to Harry for laughing at him.