A system for remotely controlling multiple application programs executing on multiple respective physical computing devices, the system comprising a first computing device, comprising a first processor, and configured to execute a first application program; a second computing device, comprising a second processor, and configured to execute a second application program; and a controller configured to perform: generating, based on first information obtained from the first computing device and second information obtained from the second computing device, a global object hierarchy comprising a plurality of objects corresponding to active graphical user interface (GUI) elements of the first application program and the second application program; controlling the first application program to perform the first sub-task at least in part by using the global object hierarchy; and controlling the second application program to perform the second sub-task at least in part by using the global object hierarchy.