Glass Bottle Label - Color on Outside, White on Inside?

Hi,

I have a bottle with a green circle on the front and a red circle on the back. So far, so good. I’m trying to get it so the “inside” of the circles are white. Imagine they’re stickers that you placed onto the bottle, and the back of the stickers are white. When looking through the bottle, the circle on the opposite side should appear white.

Here is a link to download the scene file.
https://www.dropbox.com/s/q68zdg0aedkfegm/CineversityExample_TA.zip?dl=0

I tried duplicating the circle material’s tag, changing the color to white while maintaining the same alpha, and setting the Side to “Back”, but that didn’t work. Any ideas would be greatly appreciated.

Thanks!