I have just made the jump into OS X, and since I have a little experience with linux, I am curious as to the nature and purpose of the few user groups I am seen; staff, wheel, etc. I have not been able to locate in the settings or anywhere else a gui for managing the user groups. Am I just not looking in the proper place, or do I need to download an app? Or is all the user group kung fu done at the command line level? thanks!