Analytical Panel with Openings

As per the image below, you can see I have defines a surface, then a second smaller, interior surface. I subtracted the smaller interior surface, to get the resultant surface with a subtracted element. However, after adding the last node, to define this as an anaytical panel in Robot, I realised I probably I have the wrong strategy… I probably need to define the smaller interior surface as an opening in Robot, and the first larger surface as an analytical panel. However, I can’t find any info on how to achieve the opening…

Any pointers in the right direction to define an Opening in an analytical panel?

use a void for the opening
create the big rectangle and the small and than select these to rectangles an loft them