I just use the monitor volume control and monitor with headphones. Simple. Nothing to buy.

That's one way to do it, but not how I want to do it.

griz, what you want is a radio station console. No recording studio console ever had a feature like that as that was only for radio stations not for recording consoles, which weren't designed to be used in the studio.

So your only option is really as earlier described. If you want to construct a mute switch for your control room monitors, you can do that at the input to your monitor amplifier. All you need the switch to do is to short the amplifier's input. A simple DPDT switch will do the trick.

(Muted)
Ms. Remy Ann David

You ratted me out Remy. My radio roots go back to 1967...and I just happen to like that feature.

LOL! Yeah, certainly a handy feature.

Back in the early 1980s, I custom-built a new broadcast board for NBC O&O WKYS FM. We couldn't stand the old RCA console any longer! We had a box of parts and A frame. We had a box full of API 312 & 325 cards, that were utilized for the custom in-house intercom system along with a couple of Dean Jensen/John Hardy 990 modules that were floating around. The biggest problem was the disc jockey's microphone speaker mute relay. You could always hear the on-air/mute relay click. So on my custom console, I utilized a couple of devices that were a little metal can gizmo. Within the metal can was a miniature lightbulb and a light-sensitive resistor. Yes, lightbulb not LED. That came later. Along with a capacitor to delay the relay operation, on release. So when the disc jockey switched his microphone on, it would immediately mute speakers while quickly fading in the microphone. When switched off, the microphone would quickly fadeout before the mute relay released. It was cute and quite effective. I didn't feel like utilizing a VCA nor an FET, along with its customary transistor junction distortion, etc.. But in a sense, a manual optical downward gate. Not a whole lot different from the famous Universal Audio LA-2/3/4/5's, or for that matter, any other optical limiter. You could still utilize a LED/light-sensitive resistor also known as a vactech or something like that. But a LED's illumination ballistics are way different than that of a lightbulb. One must come up with a way to ramp the voltage up and down for an LED. Of course they last longer.

Reinventing the lightbulb utilizing self produced methane gas.
Ms. Remy Ann David

KORG D16's do this.

Brilliant!!!!!!

But thay dropped this feature from their subsequent product releases.