When a first communication unit (204) receives a request from a second communication unit (102) (over an ad hoc network) to relay a call, the first communication unit will start a data call (e.g., voice over IP call) over the cellular link using the cellular phone's data capability. Since, for billing and authentication purposes, this call should be billed to the second communication unit, the cellular phone call is not set up using the standard call setup procedure (i.e. Destination phone number from the second communication unit and Originating phone number from the first communication unit). Instead, the call is setup as a "free" phone call from a first communication unit to a predefined, free number. The relay passes through the cellular link as data in the form of a data call (e.g., VoIP call). The cellular infrastructure would then route the call to its final destination.