A composite apparatus and associated methods are provided. The composite apparatus has a first function device section, a second function device section, and a remote controller section for remotely controlling the first function device section and the second function device section. An operation button double assigned with a remote control function of a specific second function group of other operation button, in the operation button group of the first function device section of the remote controller for remote control, the remote controlling function assigned to the operation button can be changed to further another remote controlling function. When a plurality of controlling functions are set to be switchable, all the plurality of the controlling functions are made to be available, for the operation button of the remote controller.