Control architectures and algorithms for large autonomous swarms are receiving increased research interest. Control of swarm systems becomes more difficult as the size of the agent swarm increases, making centralized control approaches inadequate. This paper presents the informal team assignment algorithm. By leveraging agent roles and signaling actions, the algorithm provides a local agent mechanism leading to the emergence of cooperative teams. Tested in a modified pursuit-evasion domain, simulation results demonstrate that agent roles and inter-agent signaling spontaneously create small collaborative agent teams dedicated to shared task accomplishment. The result is in higher win ratios for signal and role capable swarms.