Using/Controlling external filters

Hi all,
First time poster here…I have not seen a similar question on this forum, but apologise if I have missed it.
I have an ms20 filter clone with hf/lf cv inputs, I would like to use this as a filter for the AK by sending envelopes to the external filter via the AK cv track, while at the same time using an AK synth voice for oscillators etc.

The challenge has been to find a way to have a synth track selected and playing while triggering a cv envelope, which is in turn modulating a cv linear value. I haven’t been able to find a way to do this, so far I have only seen how to select track 1-4 for pitch triggering to a cv output, but if I have missed something obvious, any assistance would be much appreciated.