Showing differences between two versions of a score

I have two piano scores of identical length which have some harmonic and rhythmic differences. I’d like to write each piece as a separate .ly file and then programmatically combine them to highlight differences between version A and version B.

I’m imagining either:
 1. Combining / “merging” shared notes, and then highlighting (in a different color) notes where the scores diverge.
 2. Displaying smaller, secondary staves (treble, bass, or both) for measures which are not identical.
Is there a clean way to achieve this? Are there any existing examples of this sort of score comparison?