With Corona's emphasis on acting like the real world, things like "object appears one way to one object, and another way to another object" are not possible. You can use rayswitch to affect an object's reflection in ALL objects, but that's as much fakery as is usually allowed :) Other than that you'd have to treat it as a photographer would, take one shot with the object appearing in reflections, remove the object, take another shot so it's in no reflections, and mask between the two images in post.