Separate a part of a rig into an independent armature including custum shapes and related mesh


from external I got a highly complicated (read: messy) armature including one big mesh, which is deformed by this mesh. The bones have custom shapes, constraints, drives and …
The setup is not my own so I cannot upload the object.

I need to divide the armature in functional groups in a way, that they are completely independent from each other. Furthermore a need to cut the mesh into parts (where nothing overlaps) according to the different separated armatures then.

Since this is a lot of work I don’t want to start with something which looks correct to me only to recognize that it was the wrong way to do it this way at the end and I need to restart right at the beginning.

In a first step I looked for a bone, which looks like a “master” to groups of sub-bones and cleared the parent of that bone. No I can move that bone independently from the rest of the armature and vice versa. But: When selecting the rest of the armature or the separated part the complete armature (rest and separated part) get selected. Therefore my separated part is still part of the original armature.

For separating the different parts of the mesh I would go EDIT mode, select the regarding vertex groups of the according bone and then P->selection. Should be easy…

But the separation of parts of the original armature into independent armatures gives me headaches…

How can I acchieve this?

EDIT: I tried to “separate” one functional group of bones via P but this separates each individually and leave a lot more mess behind as before.
Dissolving the “sub root bone” of the functional group just does that: It dissolves this single bone.
But how can I separate (or whatever terminus technicus is applicable here… :slight_smile: this functional group
and leave the relations of bones intact?