The GMI model generalizes the RMI model in three ways. First, a reference (stub) can be used to refer to a group of objects instead of a single object. Second, GMI has several ways of forwarding method invocations and dealing with the replies. For instance, GMI allows the user to express broadcast and asynchronous communication. Third, GMI allows the programmer to configure a group reference at run time to use specific forwarding and result-handling schemes. Each method in a group reference can be configured separately, and different forwarding and result-handling schemes can be combined.