We have proposed a design tool for synthesizing multitier computer networks based on the concept of molecular assembly (MA), where the network's nodes integrate intelligently together by exploiting various forces of attraction existing between the nodes. Three forces are defined and the forces are the distance force, the incoming flow force and the outgoing flow force. Our simulation results demonstrate that for a given unassembled network of 50 nodes, our design tool forms a self-assembled network and manages to reduce the traffic at the backbone by 40% in a short computing time.