Sorry, currently Octane doesn't have this feature. You can hide objects from the camera rays and from the shadows, but not from the reflection/refraction rays.
Juanjo by setting General Visibility to 0 with a light emitter you can fake the hide light reflection. Of course this apply to all you objects and is just a workaround ... but good enough in some case.
Is this a feature that might be expected in a future release of octane? Having Octane honor the Reflection Objects/Refraction Objects parameter tags in Houdini would be very useful for being able to use Octane for visual effects work.