Does your drummachine/sampler have less than 16 instruments?
Use the free instrument slots of a Zaquencer Drumtrack with another drummachine!
Either have the first drummachine put all notes through to the next one (and each drummachine is set so that they react to different notes), or hook them up to Output A and B of the Zaquencer, and set your drumtrack to output on both A and B at the same time.
You have to make sure that your two drummachines/sampler are able to receive on the same channel, but on different notes (ignoring all the other notes), as both machines will be seeing the same range of notes from the Zaquencer.
I have recently connected three drum machines to the Zaquencer for experimenting with layered percussion. A Drumbrute, a DD19 and a Volca Sample. I have chosen to give them individual tracks, and i have found out that it is possible to mute instruments on each individual track by leaving the mixer menu, select a track and then return to the mixer menu to mute the individual instruments. This is not an option for a performance, but that way you can at least preset a bunch of instruments to your liking and mute each drum track on its own if needed.
yes I´m happy to tell you that there is indeed a shortcut.
When you are in the mixer menu you can hold “Mixer” Button and then press a track button. This will select the drumtrack from the mixer menu and you don´t have to leave it to select a track.
Hope this helps!