A system and method are provided that enable a mobile device when out-of-coverage and thus unable to send or receive messages to rely on other mobile devices which are also out-of-coverage as “hosts” for their outgoing messages such that when one of the hosts comes back into coverage the host mobile device (HMD) can send the outgoing messages on behalf of the originating or “source” mobile device (SMD). The system and method may comprise a pairing procedure to determine the suitability of a mobile device being an HMD according to criteria such as battery power, memory availability and whether the device is also out of coverage. When coming back into coverage, information is obtained from the data communication system to determine whether others have already sent messages that have been provided to host mobile devices.