Hi,
I guess you are referring to the faces auto set in Guides from Mesh when you create the object.
Unfortunately changing these is not supported yet. We may try to implement this using Selection Sets in the future.
You can try doing it manually using the node graph, but I don't know if that would work.
I will take it as a feature request anyway and see what can be done in the future.
Jeordanis Figuereo (Product Designer. EPHERE Inc.)