I am using multi-column-headers and, as per the standard grid column, I can change the header template which is all fine. Corresponding to this, I would also like to be able to add a footer for the column-group but this isn't documented.
Is there a suitable work-around to achieve something similar? I'm aware I could put everything into the header, or use one of the child column's footer template. That latter doesn't really work as the item I want to add really applies to the entire group.
Ideally I am looking for something as in my attached wireframe - cell in yellow.