Conferencing & Queueing

I want to allow callers to queue for an agent and listen in on the conversation taking place with the caller at the front of the queue.

When a caller is queueing I can only seem to play them MoH.
I can place callers in a listen only mode into the conference but not, it seems, while queueing them.

Can I feed the conversation in the conference into the MoH somehow? The eavesdroppers need to be able to listen into the conversation in pretty much real time.

Any thought please? Thanks.