199—10.5 (479) Objections. All whose rights or interests may be affected by the object of a petition may file written objection thereto. Such written objection shall be filed with the secretary of this board not less than five days prior to date of hearing. This board may, for good cause shown, permit filing of objections less than five days prior to hearing, but in such event petitioner shall be granted a reasonable time to meet such objections.