Hi,
I think it's more a question of how Unity works,
what you likely want here is two trigger, one that is of the right volume, and one that is the "proximity" with a largest radius or size, have these collider on separate physics layer, and simply have your proximity based logic use the right one.
else, you can also check the distance from lists of colliders, and automate the process using arrayMaker. but I would definitly look first into having pairs or colliders for a given spot. Nothing wrong with this.
bye,
Jean