For the simulation of all aspects of V2X Communication scenarios, different simulators have to be combined and an interaction among them at runtime of the simulation has to be enabled. Hence, we have developed the V2X Simulation Runtime Infrastructure (VSimRTI) which couples discrete event-based simulators, e.g. for communication network, traffic, and V2X application simulation. The flexibility of VSimRTI allows us to vary the composition of integrated simulators depending on the specific requirements of a scenario. Moreover, optimistic synchronisation mechanisms enable us to decrease simulation time. In this paper, we combine both traffic simulators VISSIM and SUMO. VISSIM is used to achieve a highly accurate simulation of the most interesting region, whereas the more efficient traffic simulator SUMO simulates surrounding areas. We shall show that this simulator coupling reduces the overall simulation time without any decrease in accuracy. This work has been carried out within the PRE-DRIVE C2X project.