Hi @petermast,
If you're referring to the tab named "Student Groups", I don't think there is a way to get rid of it completely. You can delete all groups under that tab though, and then go to the course settings page, and under the "more options" link at the bottom, disable the "Let students organize their own groups" option. This effectively disabled the functionality of that tab, even though you as an instructor would still see it.
Hope this helps, but if you're actually referring to a different scenario, please let us know!
-Chris
