I don't have a answer to your Question.

But meanwhile i would try the following workaround:

make a long Song which is silent, an place it between each of your backing tracks.

while performing, after one Song with backing it is silent, beacuse of the silent Track.

If you want to go on with your next track, you just need to klick (possible with a Footswitch) next Track.

The only risk is, if you make a longer pause as the silent Track, you need to press Stop.

I would rather see it playing one song at a time as you can forget and it sounds bad when you talk then the next song starts!