N.Y. Mental Hyg. Law § 79.05
Except as hereinafter provided it shall be unlawful for any person to accept appointment as guardian of any ward if such proposed guardian shall at that time be acting as guardian for five wards. In any case upon presentation of a petition by an attorney of the administration under this section alleging that a guardian is acting in a fiduciary capacity for more than five wards and requesting his discharge for that reason, the court, upon proof substantiating the petition, shall require a final accounting forthwith from such guardian and shall discharge such guardian in said case.
The limitations of this section shall not apply where the guardian is a bank or trust company. An individual may be guardian of more than five wards if they are all members of the same family.
N.Y. Mental Hyg. Law § 79.05