Transfer call/s to extension to play audio?

Hi forum
I’d like to establish an internal “virtual extension” to automatically answer each call and play an audio file.
It will only have calls transferred to this “virtual extension” from a human using a real extension.
For testing, I’ll use the weasels sound file.
Do I create this “virtual extension” with Extension module, or Announcement module, or somethings else ?
Pls for any tips to wiki or man page. I’ve already searched, without success.