This paper proposes a new architecture for cooperative communication in wireless ad-hoc networks particularly suitable to emergency and safety applications. The proposed solution is characterized by the following relevant features: (a) a wireless connection between each couple of network nodes is established via multiple relays; (b) each source-to-destination link is characterized by a double string topology allowing the use of specific transmit diversity techniques for reliable communications; (c) a novel utility-based and distributed routing algorithm providing a fair exploitation of the available resources is employed. Simulation results evidence that our solution offers substantial energy savings with respect to traditional ad-hoc architectures.