Ronald Mariano, the Massachusetts House majority leader, planned to file legislation today that would force insurers to cut payments to the most expensive hospitals and doctors, a bold proposal that is likely to meet opposition from many providers. The amount the insurers saved would be used to increase payments to the lowest-paid hospitals and doctors, and to reduce health insurance premiums for employers and consumers. Mariano, a Quincy Democrat, said his plan could shave roughly $267 million off premiums, based on a previous analysis by Governor Deval Patrick's staff. "There is a wide discrepancy between the 'have' hospitals and the 'have-not' hospitals," Mariano said. "This is an attempt to focus that discussion." Given the general resistance in Massachusetts to government regulation of the prices charged by medical providers, Mariano's plan is assured to be controversial. Lynn Nicholas, president of the Massachusetts Hospital Association, said her members acknowledge that price disparities exist in the state, as they do nationwide, but members do not believe the difference is severe enough to warrant aggressive government intervention into private contracts.