Getting inputs to 2 programs at once

Hope someone can help me out, I recently got into Arduino and followed this guide How to Control Robots With a Game Controller and Arduino
I have a question regarding getting the inputs to the Arduino and to another program at the same time. I want to be able to play a game whilst the Arduino gets the input signals as well. The end goal is to make a game agnostic simulator setup, where the controller controls both the game and the Arduino.

This should be possible? I have seen a number of online streamers have an overlay of their game controllers (using things like OpenJoystickDisplay) and it looks like this is a HTML5/Java function?, so I know that two programs can get the information at the same time, but with the processing application above it needs to be the active window.

Just guessing but it sounds like this is on ether net. Simply get a hub and connect both, just do not let the arduino acknowledge as I understand it you want it to just monitor.
Good Luck & Have Fun!