Sending a single cue mix to multiple outputs

I'm set up in my studio to send 5 discrete headphone mixes to performers.

When an individual asks for a change in there headphone mix, I would like to be able to monitor what they are hearing

I have a pair of outputs sent to my monitor controller as a "mix B" in the control room

It would be awesome if I could select this output along with the cue mix send simultaneously.

Currently, only one output per cue mix is allowed