I use a Morningstar MC6 with cc commands to mute sounds/groups with on my Maschine+
I do this via Midi Learn on each Output Level after routing each to a separate group.
However this does not work when sending midi out to external synths, only with internally generated sounds/instruments/samples.
Is there any other way to mute or disable the midi sounds/tracks to stop the midi being sent to external synths.