Python Tornado server with WebSockets: Allow concurrency across websockets but doing things sequentially in the same websocket

Is there a way to run all messages that arrive to the same websocket sequentially, in a blocking way, while without blocking messages arriving to different websocket?

So let's assume someone is using ThreadPoolExecutor with 8 threads (to utilize all available cores), together with the yield statement and the @gen.coroutine decorator, every time the server runs executor.submit the task goes to some thread arbitrarily. I'd like to enforce that for a given WebSocket, only one thread will handle the tasks, in order to assure things will run sequentially.