Lawmakers across Pennsylvania are signaling a willingness to referee a fight between southwest Pennsylvania's dominant health insurer and the region's largest medical system. Highmark, a Blue Cross Blue Shield affiliate, and UPMC, the University of Pittsburgh Medical Center health system, tried for months to set new reimbursement rates for doctors' visits and medical procedures. Negotiations broke down when Highmark announced plans to buy Pittsburgh's No. 2 hospital network--the much smaller and struggling West Penn Allegheny Health System. UPMC officials say that move makes Highmark a competitor.