Susan,
       You do not understand. These people are used to being headliners and want to be paid full price as such. They would never be content with playing second fiddle to some new upstart kid who is still wet behind the ears and was probably not even born when they started singing. To have them do one song during the break would be an insult to them and that is the last thing I would ever want to do to someone of their stature.
                                             SOL