Multiple parts per Instrument for printing but individual MIDI channels for vocal guides

Hi,

I'm loving MuseScore 4. What a brilliant update!

I suspect I'm completely missing a concept here:

I've written a vocal arrangement for Tenor, Lead and Bass (attached). The Tenor and Lead lines share a stave.

How do I export each voice to different MIDI tracks or channels for creating vocal guide tracks in a DAW?

The Tenor and Lead lines are exporting as MIDI channel one since they share a Part due to being separate voices on one Instrument stave.

Thank you!

Sam.