A kinetic equation for optical-field oscillators localized in a system of coupled optical cavities is considered. The cavities exchange directed nonclassical optical signals, which are attenuated, split, and mixed by linear mixing devices (partially transmitting mirrors, etc.) in an arbitrary manner. The form of the contributions to the kinetic equation describing signal exchange is determined for optical systems of general type, excluding those containing closed paths for optical signals. The self-consistency of such a description is discussed.