Create Queue + Do a task when it reaches a certain number

Hi There,
I’m trying to create an asterisk script which calls 10 different numbers and play them a sound file.
This part is easy and finished
However then I want to have them press a button, and once everyone has pressed a button, a new syncronised sound file plays.
The way I have thought of doing this is by connecting them all to an extension with a queue.
Once the queue detects that 10 numbers have connected it plays the sound file.
At the moment I’m trying to create a version which works with just 2 numbers.

Anyone got any bright ideas?
I imagine it is relatively easy, but it’s taking me a while to figure out!

THanks!

Why a queue? I’d go for a meetme room…