Note for this feature to work you must have Perfect Metadata.
Got several versions of a song from different publishers? Pick any one, put it into a playlist. Later, when viewing that playlist, you can pick which version you want (ie: the album from whence it came), right in that playlist, even in the Rotation list. This is for the situation where the singer gets up to the stage and starts to hear their song and says "Oh this is not the version I meant, I want to try a different version of this song". In fact, listed next to the album name is the current rating (0-10), so if you've rated the songs, pick the one with the highest number.
The old way: You have to switch back to the Library, search for the song again, sort by album, locate the one you want to try try, drag THAT one into the singer's playlist, switch BACK to the playlist, drag-reorder the newly added song to the correct position, delete the old song you didn't like, and double click the song to start up the playlist again.
The new way: Click the album popup and pick the one you want.