Basically a MIDI filter with mutes: filter channels; filter the common controllers.

A belated upload from Lockdown 1, built & left to languish in response to this thread from the Organelle forum;
https://forum.critterandguitari.com/t/midi-thru-box-with-channel-muting-pads/6042

MIDI IN needs to be set to “Omni”. (Not sure I ever established this as an absolute fact…)
MIDI OUT needs to be disabled.

KEYS 1-16 mute/unmute midi channels 1-16 respectively;
KEYS 19, 21 & 23 (top row, three keys furthest right) select notes, pitchbend & modwheel respectively and route them to the midi filter above;
AUX mutes/unmutes all midi channels at the same time whilst preserving the selected midi parameters;

Keys 17, 18, 20, 22 & 24 do nowt;
Knobs do nowt.

On load, all midi messages are let thru. Selecting ‘note’, ‘bend’ and/or ‘modwh’ includes them in the midi filter. CAPITALS = affected by filter; lowercase = midi passed thru.