The difference between this work and the bulk of work in distributed planning (Bond & Gasser, 1988) (Huhns, 1987) as well as with the work on black-board systems (Hayes-Roth, 1979), is that in the latter planning modules communicate among themselves on a much higher level. They communicate using a language, sometimes debate and negotiate among one another or even reason about each other. The problem-specific needs for a communication language therefore constitutes the major barrier for the widespread applicability of these techniques. The algorithm presented in this paper makes integration of different modules in one system easier because the communication among modules is reduced to a minimum and happens on an information-scarce level (only numbers are being communicated). Furthermore, modules do not have to share a global internal model or global blackboard. They are said to communicate `through the world' (Brooks, 1986).