Landmark Communications Inc., owner of The Oldham Era and its parent division, Shelbyville-based Landmark Community Newspapers Inc., has announced the decision to explore selling its properties.The company, based in Norfolk, Va., announced last week that it had hired two national investment firms, JPMorgan and Lehman Brothers, to “assist us in exploring strategic alternatives, including the possible sale of Landmark’s businesses,” according to a memorandum sent to employees.A formal announcement to employees at all Landmark properties was made Ja