Single remote gain for multiple amps

[helotaxi 46]

Is there an easy way to make one of the wired remotes into a master volume control for all of my 100.2s? My HU doesn't have a knob. I like knobs.

[sundownz 197]

Use a telephone cord y-splitter - its a completely standard telephone cord

[helotaxi 46]

Just making sure wiring them together like that won't hurt the remote gain circuit in the amps themselves.