Massachusetts health plans that rate doctors individually are spreading beyond the state's Group Insurance Commission, despite the Massachusetts Medical Society's opposition to the ranking systems. Tufts Health Plan, the third-largest health insurer in Massachusetts, says it will expand its health plan that features doctor rankings. And Harvard Pilgrim Health Care, the second-largest insurer, says it is considering offering health plans with doctor rankings later this year to consumers who are not covered through the Group Insurance Commission. The Commission negotiates health insurance for about 295,000 municipal and state employees and their families.