New York Civil Practice Law & Rules Section 906 - Actions conducted partially as class actions.

 906. Actions conducted partially as class actions. When appropriate,
1.  an  action  may  be  brought  or maintained as a class action with
  respect to particular issues, or
2. a class may be divided into subclasses and each subclass treated as
  a class.
The provisions of this article shall then  be  construed  and  applied
  accordingly.

Last modified: February 3, 2019