Cooley Dickinson Hospital expects to merge with a larger healthcare organization that would become the hospital's new owner. Hospital officials said that they are in active discussions with Baystate Medical Center, Massachusetts General Hospital and Vanguard Health Systems, a Tennessee-based organization, about such a merger. Cooley Dickinson's board of trustees expects to announce its final decision at the end of November, according to Diane Cutillo, the hospital's senior director of public affairs. "A clinical affiliation is no longer enough to meet the changes demands of the healthcare system," Cutillo said. "We're looking at a relationship in which a larger partner becomes an owner." Although she did not go into detail, Cutillo said, "With the changes in the health care financing system, we are not large enough to survive as a stand-alone entity." Cooley Dickinson had previously entered into an affiliation with the New Hampshire-based Dartmouth-Hitchcock Alliance, but ended that relationship in 2008.