[bumblebee]

That sounds good Mike. I do not think using the existing Custom fields would be a good idea because anyone could already be using them. Does it need to match for anything more than just the song number? I suppose it could also match according to how the users want to set it up, but it might have a different song title (different language for instance).
Also perhaps the 'song number' to be could be alphanumeric, so someone in different bands (or classes) could use letters in the song number.
And a find/change batch in the companion so they can be mapped to something else?