Our previous work proposes a macro model that controls the flows across naturally occurring bottlenecks in multi-hop wireless networks. The macro model resembles a conventional wired network, and allows us to apply extant research on flow control directly to ad hoc networks. In this paper, we further justify the feasibility of applying our macro model of ad hoc networks to access control and the validity of only controlling the flows across bottlenecks. We describe a simple rule that partitions the network into super-nodes. We then introduce a probabilistic geographic routing protocol that routes packets between bottlenecks to avoid congestion within super-nodes. Simulation results show that not only is the average flow in non-bottlenecked areas less than the average flow across bottlenecks, but the flows in each of the transmission areas that is not in a bottleneck are less than the flows in the transmission areas within the bottleneck.