§ 617-a. Residents; special provisions. Notwithstanding any other provisions of this article, the New York adjusted gross income and the New York taxable income of a resident individual or partner of a partnership doing an insurance business as a member of the New York insurance exchange described in section six thousand two hundred one of the insurance law, shall not include any item of income, gain, loss or deduction of such business, which is the individual's distributive or pro rata share for federal income tax purposes or which the individual is required to take into account separately for federal income tax purposes. Provided however, such individual's New York adjusted gross income shall include his distributive or pro rata share of the allocated entire net income as determined by such business under sections fifteen hundred three and fifteen hundred four of this chapter. In the event such allocated entire net income is a loss, there shall not be subtracted from federal adjusted gross income in computing New York adjusted gross income such individual's distributive share of such loss.