Continental Airlines, Houston, executives may hire Frank Russell Co. to manage all or part of its $1.2 billion in pension assets. John Morris, managing director-treasury operations, said that hiring Frank Russell for investment management outsourcing is something "we have explored, but nothing definite has occurred. "Just because we explored it doesnt mean well do it, Mr. Morris said. Research has been completed, he said, and it is too late for additional managers to be considered. He declined further comment. Asset figures come from the Money Market Directory of Pension Funds. Frank Russell representatives declined to comment.