From what I read you're saying a phone can send a message to multiple units based on tower connection. In other words without knowing the target phone number.
What Nokia or Samsung can do this? Pics or it doesn't exist.
I would think it's more a control feature that the carrier can execute from the cell tower. For example to efficiently communicate cell location info. To execute handshakes, timing, cell to cell hand overs. Just guessing based on inferences from networking.
Again, absolutely doubt this feature can be user controlled from any retail cellphone. Provide examples.