Any employee assigned from the federal government under the terms of title IV of the Intergovernmental Personnel Act of 1970, 5 U.S.C. sections 3371-3376 as may be from time to time amended, may be transferred between any office, department, commission, board or institution of the executive branch, or between branches, in accordance with the provisions of this section. Officials may enter agreements for such transfers, with the consent of the fiscal committee of the general court and, in cases where an official in the executive branch is a party to such agreement, with the consent of the governor and council. Such transferred employee shall for all purposes except supervision remain an employee of the transferor office.