Is there a way to play custom wav (or mp3) once auto batching is done?

Hi,

I use the batch function all the time, that takes a long time (20~30 min.)

While waiting to be finished, I want to be away from the computer but in close proximity.
It would be very useful if there's way to play the custom audio file when the batching is done so I can immediately return to the computer.
I know that I can create a script to play the custom sound but I only want it to play it once after batching is done.

Is this possible?