We have presented a decentralized control design methodology for regulating global functions of cooperating mobile systems. The application of relatively standard system-theoretic tools, leads to a novel broadcast-only communication structure. The feedback mechanism between vehicles is the measurement of the global variables and broadcast of their integrated values. More generally, the methods presented allow the designer to determine what explicit communication strategies are sufficient for a stabilizing decentralized control to exist. Using a simplified model, we showed that it is indeed possible to regulate global variables of a platoon of autonomous underwater vehicles, in particular, the center of the platoon and the distribution of the vehicles about the center. A relatively small amount of explicit communication is required between vehicles and that no vehicle must regulate its actual position. Further, the approach presented is scalable to any number of cooperating vehicles without the need for additional communication, although there is a practical limit on the size of the platoon.