Listen to previous takes in real time while loop recording?

I'm recording a vocal phrase in a loop and I'd like to be able to hear the previous takes in real time while the loop repeats.  (Like you can with a guitar loop pedal, some of which now come with a built in mic input). Previous takes seem to be muted in Sonar X1 by default, but is there a way to make them audible while the loop is still recording?