Oddly enough this is exactly the opposite of what people are usually trying to do. Not sure why in the heck you would want to undo discrete codes for a toggle command but here is one way it could be implemented.

If it is a hard button that you are trying to use you could duplicate all pages and make one copy with system on the other with system off coded to the hard button on each of the device pages. By manipulating a jump after the Power Toggle button press you could achieve some toggle capability. For this to work however the equipment has to work in a consistent manner, so that it's always in a known state.

Personally I feel you are much better off placing a jump on said power button to a page that has two options "Turn system on" or "Turn system off". If your components all have discrete power commands then this should yield the expected result each and every time.