I'm trying to create a dynamic block for wiring connections of our field
parts. The wire is intended to represent a "Twisted Pair"
communication cable, so there is what I'll call a "Wave" in the middle
of the block. There are two (2) line segments on each side of the Wave.

I want to Stretch the line segments on both sides of the Wave in one
direction but I want the wave to stay in the center of the block.

I'm able to get the lines on both sides of the wave to stretch
correctly, and able to keep the wave in the middle of the line block.

My problem is that the grip should remain at the end of one of the
stretch parameters, but it's not. I suspect it's not because my Move
parameter isn't moving the line segments on the right side of the wave
in the block.

I can't figure out how make the grip track with one side of the block when it's being stretched?uploads/290750/Dynamic_Wire_Stretch.dwg