I see some folks have changed out their shower head for one that has a "stop flow" feature, but I can't find that any X17Z owner has done that. My shower head and line seem to be all one piece and doesn't look like it is meant to come apart.
I was able to change just the shower head to one that has a shut off. It just unscrews where the hose connects. On sort of the same topic. I added Velcro to the sower curtain and walls to help keep water in the shower stall. I also picked up some L channel type plastic from the plumbing area in HD and added it to the top of the shower pan and caulked it. Water runs out of that shower way to easy.