I have defaults all around for Omni and for the echo.
If I have 5 midi tracks, whichever track that is in focus, that is was selected, will play midi sounds for the synth that track has assigned.
If I have ALSO selected additional midi tracks to be heard, by clicking on additional Echo buttons, then their synth sounds will be added into what is being played.
As long as I rely on the auto echo button, and do not manually select additional track echo buttons, I ONLY hear the midi for the track in focus, which is just how I am wanting it to be.
Playback will still play all non-muted tracks with data, so that's not a problem, and just because each midi track has input assigned to omni doesn't mean they all play - it's the combination of focus and echo as to what gets heard (obviously not dealing with mute here).
Bob Bone