A state or foreign savings institution authorized to transact business in the Commonwealth may establish without prior approval of the Commission a drive-in or pedestrian office opened in conjunction with an approved branch office of the institution, if such drive-in or pedestrian office is to be located (i) within 500 feet of a public entrance of the approved branch office and (ii) closer to that entrance than to a public entrance of any other financial institution. The functions of a drive-in or pedestrian office shall be limited to the ordinary functions performed at a teller window.