ok, then I repeat again, maybe I did not explain it well what I mean:
you can use this if you follow one rule: only channels of the same type can be used.
so only inputs or mix busses, exactly the same way as in the ganging menu.
then the logic is simple: only functions of the same type are coupled in the respective layer. and at these channels the SEL buttons flash, so you can see which gangings you have created.
if this is solved in this way, there is no limitation due to the flexible layer structure.