I have an application where I am installing an outdoor transformer right next to a disconnect. I am using (4) wires with the 4th wire being used as the grounded wire. This grounded wire will be connected to the neutral at the transformer and at the disconnect. The grounded wire will also be bonded to the two enclosures. I know typically that you also need to have a ground rod driven at both the transformer and the disconnect with the grounded wire bonded to both at each end. However since these two units are right next to each other can I only drive one ground rod and bond this rod to both the enclosures and therefore grounded conductor at both ends?