The electromechanical wave propagation in power systems was emphasized and investigated through mathematical models and practical observations. To mitigate this propagation, the conventional power system stabilizer was introduced before. The strategy adopted in this paper is to exploit the phenomena of disturbance propagation and reflection to provide an extra damping torque via the PSS. To counteract the propagated disturbances, auxiliary signals of the speed deviation of the first disturbed machines are sent to the PSS of the consecutive directly connected machines. To enhance the overall damping, the reflected disturbances are considered as new propagated disturbances in the reverse direction and are counteracted as the propagated disturbances. In brief, the neighboring machines speed deviation signals are used as extra inputs to the PSS of each machine. The simplified model of the Western North American power grid and an academic power system model are simulated to illustrate the effectiveness of the proposed strategy to mitigate electromechanical wave propagation and the associated oscillations.