Control multiple instruments via one instrument

It is possible, but you can’t render the output from one channel.
the best advise i can give is connect three instruments to the same midi instrument and channel and then assign each instrument to a dedicated track.
For editing these notes (deleting one note on one track and having the other ones on the other tracks deleted automatically) i would advise http://forum.renoise…gement-console/ .
Something did happened in 2.8.1 that requires some fixing, so that version is still a bit dangerous when changing the visible instrument amount of the list in the gui, otherwise it should work reasonably fine.