A method, a gateway, a synchronization server, a corresponding terminal and a system for transmitting a message intended for a first terminal, referred to as a destination terminal, from a second terminal, referred to as a source terminal, to at least one third terminal, referred to as an associated terminal, sharing a same identifier with the destination terminal. The method includes, following reception of the message by a gateway, transmitting from the gateway to a synchronization server the message by using a first signaling protocol and recovering by the at least one associated terminal the message intended for the destination terminal from the synchronization server by using a first synchronization message.