[Geoff Bacon]

Assuming you have a small number of ratings e.g. 1 to 3, could you not just use multiple collection names (a song can be in more than one collection)
e.g
"Band A"  All songs for Band A
"Band A-1"  Songs for Band A that are performance ready
"Band A-2"  Songs for Band A that need a bit more practice
"Band A-3"  Songs for Band A that need a lot more practice
"Band B"   All songs for Band B
etc

You could then choose "Band A" to see all songs for that band or "Band A-1" to see all it's performance ready songs e..g. use "Band A-1" when editing a set list

Obviously, you would have to make sure that you don't have a song in "Band A-1" and in "Band A-2" (but that shouldn't be difficult)

Actually, It looks like you could use "SONG TITLE FORMATTING" to display the Rating in the lists (which would mean that you wouldn't have to maintain separate groups like the above) - see page 17/18 in the MSP manual

Cheers
Geoff