[Geoff Bacon]

I just use a 3 letter mnemonic  at the end of each song name  to indicate which group it is in e.g. 
Johnny B. Goode - U3A
Johnny B. Goode - MUJ
Johnny B. Goode - Pub

Over time, songs may diverge between groups, and this lets me modify a song without it affecting the same song in a different group.
You can still put each part into it's collection (in your case, Trumpet, Cello, Orchestra)

It sounds as though you are using a musical score that contains 3 or more parts and that you are creating a copy for each part.
In this case, you could use a .csv file when importing the score - each line in the csv file specifies the page range for that particular part. This means that there is only one physical copy of the file on the tablet/pc. I would recommend using multiple copies of the file if it is subject to change.

When creating songs, I think you should try to do all the work on the same tablet and then use that as the master when synching databases

I believe that song versioning would handle this for you (Mike has said that he will support this at some point but I've no idea what his timescale is)

I'm  sure there are other mechanisms but this low tech method works for me.

Hope this helps.

Geoff
PS: I don't use Song IDs or synching!