A communication system is provided that sets up a group call, originated in a first originating network, in a second originating network when insufficient resources are available in the first originating network, wherein the first originating network is one of a narrowband network and a broadband network and the second originating network is the other network of the narrowband and broadband networks. An infrastructure device of the first originating network receives a first group call request from an originating mobile device and, in response to receiving the request, determines that insufficient resources are available in the first originating network for allocation to the mobile device for the group call. In response to determining that insufficient network resources are available, the infrastructure device arranges to set up an originating leg of the group call for the originating mobile device in the second originating network.