A system for (and a method of) selectively establishing communication with one of plural devices associated with a single telephone number during a disaster or disaster recovery period. The method can offer disaster recovery to an enterprise depending upon its size, financial well-being and desired capabilities. For example, the enterprise has the option of owning or renting all of the equipment required so that it may perform disaster recovery on its own and with little outside intervention. The enterprise may own some or none of the necessary equipment and contract with a service bureau so that the bureau provides recovery equipment when needed. The system also provides for roll call, priority preemption and seamless switching services to and from circuit and packet communication devices.