grounding back to back install
What is the norm for grounding/innersystem bonding on a back to back type install (meter base on exterior brick wall/main panel directly behind it in interior garage wall)? Home is 30 years old and panel currently grounded to copper cold water pipe via #6 bare copper wire ran through the attic and down wall cavity in the laundry. I believe this was up to code when home built. Previous home was pier and beam with main panel in the middle of the interior of home. #6 ran down under home to two ground rods on opposite side of where service came into home. Current home is slab. Do I bore a hole through the brick behind the main panel (under the meter can) and pull the ground through and down the exterior wall (possibly installing one of those new intersystem bridges (so phone/tv can be bonded at same point) or do I run ground inside wall cavity and bring it out through the bottom brick right at foundation level? The ground wire should not be coming through the meter can right?