The Baltimore Orioles are ending their relationship with Aramark, the concessionaire at the team's Camden Yards ballpark since it opened in 1992. The Maryland Stadium Authority, which owns the park, says it is in negotiations with another concessions provider who would begin operating at Camden Yards next year, but would not name it because a contract has yet to be signed. This season, Aramark operated at a dozen Major League ballparks, the most of any concessions company.