Thanks for the post - I ran into the same issue.
Where it gets different for me is that I am trying to make just an old fashioned simple VCA where the voltage of one signal controls the amplitude of another signal.
My thought was just to (in my Modulation Matrix) route the “output” of Zone 1 as my “source” to my “destination” of “Bus 1”.
In the same layer but second Zone, I would use “Bus 1” as my “source” and and route my “destination” to my “level” of “zone 2”.
any thoughts? i completely agree with your analysis, but where the ability to cut and paste gets tripped up is using the “output” as a “source”
there might be an obvious answer to this that I am not seeing? any ideas?