A method can include receiving member information from first member devices at a first gateway UE in a device-to-device (D2D) LAN. The D2D LAN can include a first sub-LAN and at least one second sub-LAN. The first sub-LAN can include the first gateway UE and the first member devices. Each of the second sub-LANs can include a second gateway UE and a set of second member devices. The first and second gateway UEs can be connected with sidelinks. The member information can indicate a first DEVICE ID associated with the respective first member device. A first member device list including the first DEVICE IDs of the first member devices can be updated based on the received member information. A first mapping update message including the updated first member device list and a first gateway ID of the first gateway UE can be broadcast to the second gateway UEs.