You can Set up filtering Midi cc in the preferences/Midi.
One Midi-instr is bound to one Midi-out/channel. So you could set your second Sound On the synth to the Same channel.
Or clone the Track würg anothrr Instrument…
Yes, cloning means copying a track at a certain timestamp, it is no reference.
Well actually for this reason there is the Midi-Thru-Port of a synth.
Say you have SynthA and SynthB and want to layer two sounds on one Renoise instrument.
Connect Midicable PC Midi-Out-1 → SynthA Midi In
Connect Midicable SynthA MidiThru → SynthB Midi In
Set SynthA Sound to Midi-Channel 1, SynthB Sound to Midi-Channel 1
Set RenoiseInstrument Midi-OutputDevice to PC Midi-Out-1, Midi Channel 1.
When you play the instrument, both sounds from both synths are played at the same time.