bambam_101,

In addition to BluPhenix's approach (watch out for the typo's), you could accomplish the same effect without ProntoScript by defining five "Home" activities. On each of these "Home" activities the PageUp and PageDown buttons would jump to the next or preceding page in the circular chain. On each page, the OK button would jump to the appropriate device activity.

In any case, the basic keys, such as VolumeUp, VolumeDown, Mute, ChannelUp, ChannelDown, etc. on the respective "Home" pages should control the appropriate device.