Split-track accompaniment CDs don't work

[Songbird]

I buy accompaniment CDs for my youth choir at church. The songs come in split-track [with music on one side and singing on the other] and stereo accompaniment versions on the CDs. Is there a way I can change the keys of these CDs? So far I have not been able to get it to work. For one thing, a song goes from #77 to #82 so I can't just put it track #77. That will only be the first portion of the song. Any help would be great!
Thanks.