The pipe that the shower head attaches to moves around when I touch the shower head. I want to install a shower head/hand held replacement and this is going to cause the pipe to continuously be moving. I am concerned about developing a leak in the wall. The pipe comes through cultured marble, so I cannot get to the connection. Is there a flange that tightens around the pipe and also will allow me to attach it to the cultured marble? I do not want to epoxy or otherwise cement something to it that will degrade from the apperance, but haven't been able to find a solution. Any suggestions??