Tell them that your bedroom and your sons bedroom is in the Melrose part of the property. He sleeps in Melrose.
This may help.

I almost believed you until you said that Melrose has a great education system.

Can you find the previous owner to get the low down. who told you he cant go to Melrose? Does your address say Saugus or Melrose I think if you provide the required documentation when registering they cant deny you.