An easy fix could be creating two different material slots with two different domains. To create two different materials slots you have to go in your 3d software of choice. In this way you can have your opaque face with the default material domain:

I set the double sided to true because as I understood you want to see the opaque face from every angle. For the other faces you could have the material set to translucent in this way:

Don't mind the nodes or the other stuff. In the end you should have something that look like this:

With a few tweaks you should achieve exactly what you are looking for.

An easy fix could be creating two different material slots with two different domains. To create two different materials slots you have to go in your 3d software of choice. In this way you can have your opaque face with the default material domain:

I set the "two sided" option to true because as I understood you want to see the opaque face from every angle. For the other faces you could have the material set to translucent in this way:

Don't mind the nodes or the other stuff. In the end you should have something that look like this:

With a few tweaks you should achieve exactly what you are looking for.