How to Cast to "None" in order to overwrite a target pinpoint?

I try to realize a splitscreen local multiplayer game. I try to implement ignoreInput for different splitcscreens. Due to the regression of multiple player controllers for a keyboard, Multiple playercontrollers using keyboard - Character & Animation - Epic Developer Community Forums, I came to a situation, where I think it would be good and useful to have the option to use a “Cast to a specific Object” node, but than having this node actually pointing to nothing.

Please take a look at my screenshot. At the right side you have the “target” pinpoint. I try to overwrite this via “none” at runtime, to block any user input for those functions. But I dont know how to realize a Cast to a specific Object node, and than pointing to no content.