Shaving rims

Anybody heard of a place where you can send your rims to and they shave the backside of the rim where it meets the hub, so that your rims will tuck???? Somebody told me that they saw it in an old Minitruckin' mag. Im tryin to tuck 20x9's on a Nissan Frontier. Doesnt look like the back will tuck. Any advice?????????