This paper proposes an analytical method to determine the occupancy distribution in a group of links of elastic optical networks that service multiservice traffic streams. The method is based on a modification of the recursive Kaufman-Roberts equation, which allows one to take into account the influence of two system factors on the possibility of accepting calls of multiservice traffic streams. The first factor concerns the specific structure of the system, which is a group of links modeled as a limited-availability group. The second factor is related to the requirement of selecting adjacent frequency slot units. The proposed method, taking into account the dependencies mentioned above, relies on selecting a representative microstate for each macrostate, with its conditional transition probability closely approximating that of the given macrostate. To assess the precision of the proposed method and the underlying assumptions, tests were carried out for different capacity values of the system and different traffic values offered. The results of the research obtained show that, from an engineering point of view, the proposed model is characterized by satisfactory accuracy.