N.Y. Estates, Powers & Trusts Law § 2-1.8
fiduciary to collect taxes from property taxed and transferees thereof
(c) Unless otherwise provided in the will or non-testamentary instrument, and subject to paragraph (d-1) of this section:
(d) Subject to subparagraphs (1), (2) and (3) of this paragraph, any direction as to apportionment or non-apportionment of the tax, whether contained in a will or a non-testamentary instrument, relates only to the property passing thereunder, unless such will or instrument provides otherwise.