I understand you are looking for a way to simulate a multi-agent Reinforcement Learning environment. Unfortunately, the Reinforcement Learning Toolbox currently does not support multi-agent scenario. You would need to write your custom environment and training algorithms for such scenario.
Due to large amounts of request on this feature, the development team is actively working on the multi-agent feature now and it will be available in a future release. If you decide to write your own environment and training algorithm, the following documentation would be a good place to start: