The deal adds to a run of cash-outs in the suburban office market by the New York-based private-equity giant. : Blackstone Group flipped a Deerfield office building for $47 million as it continues to cash out of the suburban office market.The New York-based private-equity firm recently sold the 294,000-square-foot One Parkway North building to a venture led by Miami-based Horn Eichenwald Investments, property records show.The deal comes just 2½ years after Blackstone acquired the five-story building along Interstate 94 as part of a $3.3 billion portfolio acquisition from GE Capital Real Estate in 2015.