How queued users can listen the current conversation?

Hi, I have 4 customers who need to speak with an expert on the phone but that expert is already in call with the first customer in the queue.

So the 4 customers need to be queued but they don’t want to listen a stupid waiting music, they want to listen the conversation between the expert and the first customer.

So how can do that with Asterisk ?

Thanks in advance for your answers.

Asterisk does the thing you tell to do, so if customers listen “stupid music” then dont use MOH, if you want a multi-person call dont use Queues use Bridges.

I imagine that that would severely inhibit the first customer as they would not want to give away business information to strangers.

Also, the difficult bit would be starting the subsequent callers listen only, then switching them. Otherwise they would probably push to jump the queue.