You would need to modify the core files of UE4 that interact with the OS to always listen for input events to do (if that is even possible), but I would not recommend doing so. Overriding default behavior of the OS will create more problems than it’s worth. Potential security issues would be one reason as you could be opening a backdoor into the OS for hackers to exploit, and is generally something to avoid unless absolutely necessary.
I’m curious why you want to add that behavior though, are you launching a separate program along with the game?