Answer:
The easiest way is to create a contact solid between both surfaces. The contact solid allows you to precisely describe the contact properties of the surfaces lying on top of each other. In the FAQ "How can I quickly create a contact solid between two contact surfaces in RFEM?" you can find information about creating a contact solid.
If the contact conditions play more of a minor role and both surfaces have the same material properties, you could also simply increase the thickness of a surface at the relevant location and use only one surface.
