Changing the Mouse's Range for OnMouse events

I am working on a project where a button is located far away from the elevator. Once the button is clicked (OnMouseUp) the elevators animation is activated.

I want to know how would I shorten the distance the mouse requires to activate the buttons script.

In the Image 1 below, I want it where my character must be within a few feet in order for the script to activate, but as of now Image 2 shows that even that far away I can click the button and the elevator moves.

Also would this way shorten the range for all the Mouse events such as OnMouseOver and OnMouseExit?

IMAGE 1:

IMAGE 2:

Heres my code:

 function OnMouseUp() {
     
     elevator.animation.Play("Elevator");
 }