Short description:

enable advanced mode

On EMX, change clock to EXT, and change MIDI filter PCEN to XXX0
(only allow note data in)

Change layer 10 to score (or bounce mode)

Drop Layer 10 to -2 octaves

The lower few notes now control the drums of the EMX!

Layers 1 - 5 control the synth voices.

This works even if (and probably better if) all the electribe voices
are supposedly solo'd / muted away

Detailed video coming later