In this paper, we consider the multiple base station cooperative transmission, a new technology being developed to lift the interference limits on wireless network. In practice, the biggest challenge facing multiple base station collaboration is the stringent requirement of the high-speed backbone to enable information exchange, especially for large deployment. We address this backbone issue and propose to define a collaborative zone within each cell. Only those users within the collaborative zone will be served by multiple coordinated base stations. Whereas users outside the collaborative zone will be served by a single base station as in a conventional non-collaborative scheme. The criterion defining the collaborative zone is proposed and designed in such a way that the users outside the collaborative zone sacrifice only marginal potential collaboration gain in terms of achievable rates. Since the amount of information to be exchanged will be a square function of the number of users served by the collaborative base stations, the introduction of the collaborative zone can reduce the backhaul overhead significantly.