An example project showing how to send input message to multiple components with the new Unity input system.
When using the new Unity input system and the PlayerInput component, it is not possible to forward input messages to multiple objects. This is a common use case when you want to have a single player controller sending inputs to multiple game objects.
The scene SinglePlayerMultiplePlayerInputs shows a simple example of this issue. Two separate input actions control the green and red balls with the left and right sticks on the gamepad or the WASD and arrow keys on the keyboard. A third object listens for the P key or the start button on the gamepad to pause the game. The red ball, green ball, and UI canvas all have PlayerInput components, but only one of them will receive input from the input system.
The problem is that the PlayerInput component is designed to be used with a single player, so when you have multiple PlayerInput components in the scene, each is assigned a user and mapped to an available controller.
The scene SinglePlayerSingleInput shows one way to solve this problem. It has a single empty Input object with the PlayerInput component on it. It takes this input and sends it onto to each of the game objects that requires it.