Currently you typically have a HEAD group in front of the BODY (so the chin is in front of the neck etc. You may also have front hair dangling in front of the body as well.
But it is hard to have +HEAD (an independent group) and rear hair (to be displayed behind the BODY). The front and rear hair should be both controlled by the head movement.
It would be nice to have a better way of having rear hair attached to head movements, but be behind the body.
I would suggest having a +REARHAIR group as a pattern, so depth of layers controls depth of display, but where you can “attach” the rear hear to the +HEAD group which is not a parent.
(A few approaches have been suggested in the forums, but none of them work properly. I only get rear hair to work when HEAD is not an independent group, so BODY and HEAD and REARHAIR are all part of the same group.)