multiple players/single input--anyone got it working?

I have three 90's, each on its own S-Link. I only have (and want) a single CD input on my preamp. I bought an MSB Digital Director and plugged the three changers into it; the output of the DD goes to the preamp CD input. All CD connections are digital.

What I expected to happen (based on the DD description) was that only the active player's output would be passed through the DD. Unfortunately, I figured "active" meant actually generating output from playing a CD, while DD treats any player that's turned on as active (apparently, the signal the DD detects from an idle player is a string of zeros). This of course, completely defeats the only reason to have the DD in the first place.

So, is there any way to truly "mute" the output of an idle player via an S-Link command? If I can get an idle player to be completely silent on output, then the DD would work as I need it to.