With the emergence of the Internet of Things, billions of new devices will be wirelessly-connected to the Internet in the next decade, thus yielding a growth of the data traffic, especially in the network infrastructures maintained by mobile operators. Intermittently-connected hybrid networks (ICHNs), which combine an infrastructure part and loosely-connected mobile ad hoc parts, offer interesting perspectives to cope with the growing data traffic. Abstract. This paper presents a decentralized unstructured peer-to-peer overlay system that aims at supporting communications in ICHNs deployed in wide geographical areas. It also presents the simulation results we obtained for our system for an ICHN composed of a few hundreds of fixed stations (with Internet access) and thousands of mobile devices used by people to exchange data while roaming a medium-size city.