I want to add a Supertip to a custom group on a custom tab on my Ribbon. Although the XML code validates, it doesn’t display when I mouse over the group name

Can groups have Supertips? I’ve found conflicting views on this point. Also, what is the property on a System tab/group –such as Home/Alignment that creates the little square in the bottom right corner of the Alignment group that opens a pop-up when you mouse over it? Can that property be added/customized in a custom XML group? Thanks for reading.