Have you considered applying the GDL object in smaller panels avoiding the openings with an offset if appropriate to align the joints?
Rather than program the GDL I might have been considering using the Profile Manager to draw the joints. The Profile tool isn't limited to sections, it can be applied to elevations as well.
Or at the most basic level just use columns and beams for the joints.
Obviously the latter two may not be appropriate if you have a lot of repetitive work with preset grids...
Apple iMac Intel i9 / macOS Sonoma / AC27UKI (most recent builds.. if they work)