In a distributed discrete-event system with decentralized information, agents at the various sites (e.g., controllers or diagnosers) may be required to communicate in order to correctly perform some prescribed tasks. Bandwidth, power, or security constraints motivate the design of communication protocols among agents that minimize the number of required communications. This note presents an algorithm that can synthesize such a communication protocol given a set of "essential transitions" that constitute the initial required communications. The synthesized communication protocol is shown to be minimal.