Callers should have the option to be able to route through a IVR and press 0 to then be routed to an call queue. If the agents don't pick up in a certain time then the call gets sent back to the IVR where the caller can then press 0 and be sent back into the call queue.
When callers dial a company number, that call is sent to an auto-receptionist, they are then routed through a custom rule to the ring group, if an operator doesn't answer the call within 25 seconds then the call is routed back to auto-receptionist. If the caller presses 0 to speak with the operator then the call gets routed back to the call queue. If the operator doesn't pick up the phone within 25 seconds then the call gets sent back to the auto-receptionist. If the caller presses 0 again then they will be allowed to go through the loop and be able to press 0 and wait for an operator for as many times as they would like, or for a set amount of times before the call is sent to voicemail or disconnected.