What exactly are you trying to do?
If you want the player to move close to an object before using it, just use the region script triggers to set a boolean when entering, and the surrounding regions when leaving.
But I doubt that you want to disable the "automatic walkto", so I guess you want to use this for an object, which can be seen by the player, but not yet reached, for there is something to be done before (open the cage, lower the bridge or something similar).
In this case, you can use booleans to reflect the states, and if the player clicks on something behind our imaginary bridge, the script will check wether "BridgeLowered" is true, and if it is not, it can output "I cannot reach this from here".
The same works for objects on "the other side of the gap", if the right part of the scene is reached from other screens, not from this one. In this case, the simplest way would be to set up two matching scenes, one for the right part and one for the left, for example, and hardcode the "cannot reach that from here"-outputs on the opposing side.