Section 1004. When joinder unnecessary

Except where otherwise prescribed by
  order of the court, an executor, administrator, guardian of the property
  of  an  infant,  committee  of  the  property  of  a judicially declared
  incompetent, conservator of the property of a conservatee, trustee of an
  express trust, insured person who has executed to his insurer  either  a
  loan   or   subrogation  receipt,  trust  agreement,  or  other  similar
  agreement, or person with whom or in whose name a contract has been made
  for the benefit of another, may sue or be sued without joining with  him
  the person for or against whose interest the action is brought.