Help.
I am part of a charity helpline, and we are trying to find a way of making a training aid.
What we have is 3 rooms, lets call them 1, 2, and 3.
I need a facility where the person in room 1, can speak to a person in room 3 using a telephone, and that a group of people in room 2 can hear both sides of the conversation.
I do not need the telephones to be connected to any network, the phones can be specific to this training aid, but I do need reasonable quality and reliability.
Any Advice would be greatly appreciated, I am happy to look at building something or if there is an off the shelf suggestion that may be ok too.