Anyone familiar with New York laws?

I am the birth mother of an open adoption that occurred 9 years ago. We live in the same town. I have been trying for months to see my birth son. The adoptive parents (now divorced) do not want that to happen. They say I can see him only if I bring my 11 year old daughter because that’s what was agreed upon…that the siblings would have a relationship. This is news to me. I want to see him and think it is a healthy thing because he already knows who I am. I don’t think I should HAVE to bring my daughter. This is in New York State. Does anybody know my rights and new York state laws?