Steam Audio

Curious if there’s anyway to add multiple phono materials to a single mesh?

For example say I have a wall. Interior and exterior surfaces. I want the outside to brick/concrete for occlusion/reverb and the inside plaster.

Hey, I´m currently on 4.27 and want to try out the steam audio plugin, but when I add Geometry Components to my Actors and then try to export i get the Error: “No material specified for object”. Any idea what the problem is ?