(a) The plaintiff shall serve a copy of the order for possession upon each defendant and his attorney, either personally or by mail:
(1) At least 30 days prior to the date possession is to be taken of property lawfully occupied by a person dwelling thereon or by a farm or business operation.
(2) At least 10 days prior to the date possession is to be taken in any case not covered by paragraph (1).
(b) A single service upon or mailing to one of several persons having a common business or residence address is sufficient.