A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
Create a notebook with that sub-structure (the section group) and store it as a notebook template (described in the link from Tim).
If you need the sub-structure (section group) open the template in the usual way to a new temporary local notebook.
Then move (copy is unavailable) the sub-structure by right click to the target notebook. You may have to rename it before the move. Now close the temporary notebook (and delete it in Explorer).
Bernd