[DonC]

Would something like this work?
Snippet 1, song 1 = song 1 measures 1-100, [uses pages 1-20, cropped]
Snippet 2, song 1 = song 2, measures 101-200 [uses pages 20-40 cropped]
Snippet 3, song 1 = song 3, measures 201-300 [uses pages 40-end cropped] 
Each snippet is treated as a separate song.
Set list = snippet 1; snippet 2; snippet 3, arranged however you want.

If I understand you correctly that should work.
I have used this several times, 3 identical files with different file names.
Then you can set the pages for each file separately.
When we have versioning it will be great, but until then, this works.