HOw to extract/Export individual SATB MIDI parts?

@clive
Selective export to MIDI isn't a possibility yet, but has been requested before, so should become a feature this Spring. For now, modern sequencing/DAW software should provide a way to remove parts in 2-3 steps, particularly with keyboard shortcuts. We'd be glad to get a better idea of your situation, and/or provide some help over email in that regard.