In this paper we consider a model in which agents have complete infonnation about their neighbors and, possibly, incomplete infonnation about the rest of the environment. We consider two different informational frameworks. In the first, agents do not have priors about the relevant characteristics in the rest of the environment. In the second, agents are supposed to have priors about the unknown characteristics. We present a mechanism which implements any social choice correspondence satisfying monotonicity and no veto power in both informational settings for every possible prior thus requiring little knowledge from the point of view of the designer of the information possessed by agents about the environment.