So with the new Output FX you can send the sidechain CC message to another track! 
There is multiple ways to do it, but the easiest (for me) is like this:
Track 1 (drum machine):
FX1: Output → to the actual drum machine, so the midi is sent directly to the drum machine without the added FX (which we’ll filter out later)
FX2: Envelope → Sidechain set to the kick drum note / Destination midi CC of the volume/any other parameter
FX3: Filter → Filter out all notes and midi CC except the one set as destination in Envelope
FX 4-8: Output with destination to any synth(s) you want the parameter to be modulated by the envelope CC
You can also just set the track output to the destination, as the actual notes are not sent to this because of the filter in FX slot 3.
Still, it would be much easier and cleaner to just have an option to set the output port+channel inside the envelope FX… It would also make it easier to send different Envelopes with different midi CC’s to different outputs.
Hopefully in a future update 