Well, exactly what I'd do would depend on why I was splitting up the tracks, how "sympathetic" I had to be about putting the splits in logical gaps in words--and whether they were going to stay separate or need to be spliced together again later.
Perhaps if you explained exactly what you're doing I could be more specific.
Certainly Dobro is right that the Razor Tool is probably the way to do the actual splits but then what you do with the chunks can depend on what you want after that.