Don't hate the playa . . . love the game:
Music libraries that don't have splits for their music tracks significantly limit your creative choices and limit your mix possibilities.
If you have to take it off the shelf, chance are you will have to make compromises. So be wary.
Quality music catalogs have splits available on most tracks and getting splits on music tracks allows you to turn up, turn down, add or take out instrumentation or vocals and, in general, gives you creative flexibility so you can get a tight fit to your picture and great results. Importantly, it allows you to customize the track if you need to add (or take out) that extra special somethin' somethin'.
How do I know whether or not the music track that I like has splits available?
(just ask the music library supervisor and they will let you know . . . )