In a court document filed Thursday, UPMC accused Highmark Inc. of trying to have it both ways by pursuing a lawsuit presuming it is being harmed by the hospital system's advertisements, while at the same time telling some audiences that it isn't losing market share. "Highmark has taken to bragging in other venues," UPMC's filing said, of "alleged marketing successes." Highmark has said publicly that it was having a "very good July renewal period," the filing said, and that it's "doing extremely well maintaining our market position." Highmark called the filing "part of UPMC's misleading campaign to scare Highmark members into believing that they did or will shortly lose their relationships with their current UPMC doctors."Highmark members will continue to have access to UPMC hospitals and physicians through June 30, 2013." Highmark sued UPMC in U.S. District Court in July, claiming that the health system's "Keep Your Doctor" campaign falsely contended that the insurer's customers would lose in-network access to many regional hospitals in the middle of next year.