Multiple audio sync files in a piece (Choral Learning tracks)

I will explain what I am thinking first. 

I have a piece of music in Noteflight, a 4 part choral score. I can currently only sync 1 audio/video performance file at a time, so at best I can only have full performance audio for the one file.

What I would like to be able to do is add a part predominant audio file for each part and then be able to control the balance in the mixer like I can with the native sounds in noteflight.

This would be much easier than making separate copies of the noteflight file and syncing audio up for each part.

With it all integrated into one score, you could do part predominant, or part missing, and you would be able to hear real singing versus computerized tone. This would be beneficial for choir students as they often learn timing from cues, modify vowels or tone color based on what is happening around them. 

From the Soundcheck end, this would provide the most authentic and natural assessment of voices like students are used to in person.