Radio frequency (RF) recharging can extend maintenance-free operation of wireless sensor networks. However, the period between recharging is limited by the distance between the most distant sensor node and the master which sends out recharging pulses. To increase this period, we propose a scheme in which nodes are logically grouped into circular zones centered at the master, so that nodes in a given zone act as relays for their counterparts in the more distant zones. We describe and analyze a polling MAC protocol that supports zoning and relaying through a probabilistic model of the energy depletion process as well as a queueing model of packet transmission process. Our results indicate that zoning extends the time interval between recharge pulses and leads to equalization of node lifetimes.