A IP telephony service allows customers to form user groups. Each user group can include multiple members, each of whom have their own telephony device. When a member of a user group sends an outgoing communication from one of the telephony devices associated with the user group, the service obtains communication handling instructions for the user group. The outgoing communication is then processed in accordance with the handling instructions. This could include sending copies of the outgoing communication to the telephony devices of other members of the user group. This could also include sending the outgoing communication with an origination identifier associated with the user group, rather than an origination identifier associated with the member's telephony device.

A mobile communication device is provided with a processor. The processor is configured to receive a request for starting a Mobile Originated (MO) service, determine a plurality of remaining usage quotas for the MO service, which correspond to a plurality of subscriber numbers, and select one of the subscriber numbers for starting the MO service according to the remaining usage quotas.

Methods and systems for sharing data usage by a plurality of SIM cards at a plurality of network devices are disclosed. Each of the plurality of network devices is capable of housing at least one SIM card from the plurality of SIM cards. The method comprises the steps of determining the total data usage allowance. A remaining total data usage allowance is determined by either retrieving it from a carrier server or by subtracting aggregated data usage information from the total data usage allowance. The method further comprises restricting use of one or more of the plurality of SIM cards when the remaining total data usage allowance is below a first threshold until the remaining total data usage allowance is above the first threshold. The total data usage allowance is changed to a first value periodically or according to an administrator's instruction.