(a) The plaintiff shall name as defendants
(1) the mortgagor;(2) the personal representative, heir or devisee of a deceased mortgagor, if known; and(3) the real owner of the property, or if the real owner is unknown, the grantee in the last recorded deed.(b) Unless named as real owner, neither the mortgagor nor the personal representative, heir or devisee of the mortgagor, need be joined as defendant if the plaintiff sets forth in the complaint that the plaintiff releases such person from liability for the debt secured by the mortgage.