This paper presents the multilevel A-diakoptics methodology (diakoptics based on actors) for the dynamic load-flow simulation of hybrid distribution systems (DSs), which are power systems working at different base frequencies. In the development of the smart grid, several challenges have been identified, such as the connection of nonconventional loads, distributed generators, and interoperability between power systems working at different frequencies. These challenges have led to use simulations for designing and developing the future grid. Additionally, computer hardware architectures have evolved to allow modeling the real world more accurately. However, the existing simulation methods for power-flow analysis are not compatible with parallel and concurrent processing, subusing the existing computer power. Our approach called A-Diakoptics combines the power of Diakoptics and the Actor model to make any conventional power-flow analysis method suitable for multithread processing. As a result, the nature and complexity of the power system can be modeled without affecting the computing time, even if several parts of the power system operate at very far modes or bandwidths such as in the case of dc microgrids. This method is an advanced strategy for simulating large DSs in unbalanced conditions, covering the basic needs for the implementation of multiscale grid dynamics.