Hello- I want to have 2 mice, one on the left, and one on the right so I can switch back and forth for ergonomic reasons. I know that it is possible to have two mice hooked up at the same time, but is it possible to have the Mac differentiate I always have to go into the system preferences and change it from left to right every time I starts using a different mouse? When I change the buttons in system preferences, it changes on both mice. If this is not built into the OS, does anyone know of a 3rd party app that might provide this functionality. Thank you!