2006 New York Code - Notice To Third Party.

 
  Section 3--803. Notice to Third Party.
    Where  a  defendant  is  sued  for breach of an obligation for which a
  third person is answerable over under this Article he may give the third
  person written notice of the litigation, and  the  person  notified  may
  then  give  similar notice to any other person who is answerable over to
  him under this Article. If the notice states that  the  person  notified
  may come in and defend and that if the person notified does not do so he
  will  in any action against him by the person giving the notice be bound
  by any determination of fact common to the two litigations, then  unless
  after  seasonable receipt of the notice the person notified does come in
  and defend he is so bound.