Your other option is to build a two page configuration. ( I prefer using a NevoConnect with a sensor - either the video or voltage sensor).
The two page systems works like this:
Main Home Page has all your power on commands for all devices - so it doesn't matter which activity you choose from your main page - the power commands are sent to all equipment. Going back to choose a different activity involves a page jump to a second home page (looks the same, can be labelled the same) but all these macros do is switch inputs and page jumps.

You'll have to create a system shut down page - when if the user confirms to turn off system then power commands are sent to turn everything off then jumps to the first main home page but if they decide to leave the system on then it jumps back to the second home page.

Drew