It is considered the routing problem for which some fixed tasks must be serviced above all. Other tasks can be serviced only after realization of above-mentioned original tasks. It is supposed that each our task is the megalopolis (nonempty finite set) visiting with fulfilment of some works. In our setting, two partial interconnected routing problems arise. We suppose that, in each partial routing problem, the corresponding precedence conditions are given. Using widely understood dynamic programming (DP), we obtain the optimal composition solution for initial total problem. As an application, we note the known engineering problem connected with sheet cutting by zones on CNC machines. By DP procedure the optimal algorithm realized on PC was constructed.