Hi karelvdz

A possible solution or a starting point for one.

Started with a standard mia_x glass material. Added a samplerinfo node, attached the "flippednormal" attribute to the first term of a condition node and mapped one of the condition node out color channels to the reflectivity parameter. I hardcoded the outcolor on the condition node to 1 if true and 0 if false.

Although the sampler/condition nodes removed the reflection on the insides, the toruses were still being reflected in adjacent bubbles. Had to set a low value for the "Use max distance" parameter under advanced reflectivity to get rid of it. The greyish edge around the bubbles are from the "End Color".

On a side track a question for the gurus on the site. I did a test where I simply turned off the "Visible in reflections" attribute on the torus shapes. The reflections of the toruses were suppressed on the inside of the bubble but they are still reflected on the outside of adjacent bubbles. What gives?