V-Ray offers per-object visibility adjustments through the Visibility Properties node in the Object Node Tree. Make sure the node is connected to a V-Ray Object Output. Otherwise, the visibility properties will not be applied.

UI Path: ||V-Ray Node Editor|| > Object > Add > Object Properties > V-Ray Visibility Properties

Visibility – Determines the opacity of the entire object.

Camera Visibility – When disabled, the object appears perfectly transparent to camera rays. This option is inactive when working with the V-Ray CUDA engine.

Visible In Reflections – When disabled, the object appears perfectly transparent to reflection rays.

Visible In Refractions – When disabled, the object appears perfectly transparent to refraction rays.

Cast Shadows – When disabled, the object appears perfectly transparent to shadow rays. When disabled, the object no longer affects the GI.

Receive Shadows – When disabled, the object does not receive shadows. This option is inactive when working with the V-Ray CUDA engine.