While holding ‘Control’, click on 3 or 4 track headers.
They should all go white together [just like when one of the tracks is in focus].
Then change some routing or MIDI channel info within one of tracks.
Then hit ‘Enter’.
Just try that. That might do it.
If so, then there’s no limit to the number of tracks you can alter at once by this method.
Then, there’s an even faster way.
Say you have 10 tracks to alter.
Hold ‘Shift’ and click the first & last tracks and all the tracks in between will be selected.
You probably already know this, but if not, you can click & drag your tracks wherever you want them so that they’ll all be together first before the above steps are done.