Alternative playback of several parts with one bassline?

I would like to create a layout in which there are three staves: the lower two staves for left- and right-hand piano parts, and the upper staff for a second right-hand piano part. The idea is not that the two right-hand parts be played simultaneously by separate players. Instead, I am trying to show two alternatives for what may be played in the right hand (by a single player). For an example of what I am trying to achieve, see page 20 of http://derekremes.com/wp-content/uploads/compendium_english.pdf.

I can achieve this layout by creating a second piano player and then hiding that player’s empty left-hand staff.

However, I would also like the playback to reflect this “upper staff as alternative right-hand part” idea. In other words, when playing back the upper staff, I also want the left-hand part to play (but not the other right-hand part). Is this at all possible?

Assuming this is the only instrument in your system (which would affect bracketing) I would add a staff to an existing keyboard part and assign separate piano sound channels for each staff so you can mute them separately.

Try this:
threeStavesThreeVoices.zip (544 KB)