Massachusetts hospitals are systematically cutting back on pay and benefits for employees, according to a BBJ analysis of operating data for nine of the state's largest care providers. According to financial filings for the six months that ended March 31, a majority of the Bay State's largest hospital groups reported year-over-year declines in salaries and benefits expenses. The largest one-year cut was recorded at Children's Medical Center in Boston, which said salary and benefits expenses totaled $263.8 million in the most-recent period. The total was off 6 percent from the $281.4 million reported by Children's in 2012's corresponding period.