For real-time simulations, the fidelity of simulation does not depend only on the functional accuracy of simulation but also on its timeliness. It is helpful for developers if we can analyze and verify that a simulation will always meet its timing requirements while keeping an acceptable level of accuracy. Abstracting the simulated processes simply as software tasks allows us to transform the problem of verifying timeliness into a schedulability analysis problem where tasks are checked if they are schedulable under real-time constraints or not. In this paper we extended a timed automaton based framework due to Fersman and Yi for schedulability analysis of real-time systems, for the special case of real-time multi-frame co-simulations. We found that there are some special requirements posed by multi-frame simulations which necessitate changes and improvements in the existing framework. We made the required theoretical extensions to the framework and then implemented our extended framework in UPPAAL, a tool for modeling, simulation and verification of real-time systems modeled as timed-automata, and tested on an example.