I have been reading some of the posts about grounding after installing pex. If an existing galvanized system were grounded to the cold water main where it enters the house couldn't the old galvanized conceivably remain grounded via a jumper? If the old galvanized system were left in place and a new pex system installed around it couldn't a jumper wire serve to connect the remaining galvanized system back to the cold water main keeping the original ground intact?