This work develops techniques for modeling and distributed simulation of complex situated multi-agent systems, which are highly dynamic and possess an intrinsic spatial character. Each agent owns its spatial coordinates and acts and interacts with its peers in a hosting territory. In a distributed/parallel scenario of a typical situated agent model, the territory represents a huge shared variable. Frequent access by agents to territory information easily becomes a bottleneck degrading system performance and scalability. This paper proposes an original approach and supporting API to distributing situated multi-agent models using actors. The approach exploits time management for resolving conflicts and to achieve data consistency. Approach contribution is twofold: (a) it simplifies M&S tasks by making the modeler unaware of distribution concerns, (b) it is capable of ensuring good model scalability and simulation performance. Practical aspects of the approach are demonstrated by a Tile-World model and its distributed simulation experiments.