Is it possible or probable to get child support payments lowered if you reside in NY state ?

I am a joint custody non custodial father of an 11 year old boy. I got divorced from my sons mother 10 years ago. I have always paid my support obligations in full and on time never missing or being late with a payment even once. My question is this, since my divorce I have gotten remarried and have a wonderful wife and 3 daughters. Obviously my situation has changed considerably since my original divorce agreement 10 years ago. I know it is unlikely but what are the chances that I could get my support reduced ? I find it extremely unfair that my daughters have to do without or that my wife and I are forced to struggle financially because I am forced to pay more money per month to "support" my son than it costs per month for my other 3 children together. I understand that the system is unfair to fathers of divorce but is there anything that I can realistically expect to change or do I have to just tread water until my son goes to collage (hopefully living on campus) ?