A distributed processing environment includes a mainframe computer system having a plurality of processing sub-spaces. An asynchronous messaging service resides in each of the processing sub-spaces. Additionally, a server process application resides in a first one of the processing sub-spaces while an instance of a handler application resides in each one of the remaining processing sub-spaces. A client computer system issues a request message to the asynchronous messaging service residing in the first processing sub-space. If the server process application requires the services of the handler application to handle the request message, the server process application passes the request to an instance of the handler application selected using a load balancing algorithm. After processing the received request, the handler application returns a response to the request to the requesting client computer system via the asynchronous messaging service application residing with it in one of the processing sub-spaces.