A distributed control system featuring the coordination of functionality among peer controller nodes. The controller nodes are luminaires that are capable of controlling the ambient lighting within a building area. Within the control system, there are one or more ambient light sensors for reporting the ambient light level by publishing data packets containing sensor values. The controller luminaire nodes are members of a defined group of nodes that behave according to the same set of rules. Each controller node is capable of generating a control signal in response to detecting the data packets containing a group address to which the controller node is subscribed. In particular, a first controller node generates a first control signal for controlling a lamp if a subscribed-to group address is detected, wherein the control signal is determined by an aggregate function whose input values include the sensor values in the data packets.