If message box changes, send the message in the box (emulate clicking on it)

Hello,

I am controlling audio files and I need to essentially mimic the effect of clicking on a message box in order to tell the buffer~ which file # to play.
I've tried T B S but but it's no use. Another way to think about it would be [zl change] but instead of just banging when it changes i need it to send the message.

I think this is relatively simple but it's driving me crazy.

thanks,
Dan