The lifetime optimization problem of wireless sensor networks is widely solved using disjoint sets covers in which a sensor cannot participate in more than one cover. The proposed method gives an opportunity for a sensor to join more than one cover. The genetic algorithm is used to find the maximum number of non-disjoint sets covers to be scheduled to optimize wireless sensor networks lifetime. The investigations show that the algorithm complexity increases when the problem is reasonably divided into two sub-problems. The obtained results encourage to search for better solutions using this approach rather than that based on disjoint set covers.