“Plaintiff’s attorney must decide at the outset of the action which persons must be joined as plaintiffs or defendants [compulsory joinder] and which persons may be joined if plaintiff wishes. Plaintiff must join as parties to the action all persons whose interests are so directly involved that the court cannot render a fair adjudication in their absence. Merely being named as a party to the action is not enough. A party is not properly ‘joined’ unless properly served with summons and complaint.”
“Plaintiff is required to join as parties to the action any person whose interest is such that: In the person’s absence, complete relief cannot be accorded among those already parties to the action; or, any judgment rendered in the person’s absence might either (a) prejudice the person’s ability to protect his or her interest in later litigation; or (b) leave any of the parties before the court exposed to a risk of additional liability or inconsistent obligations. Joinder may also be ordered if an existing party is exposed to a ‘substantial risk’ of multiple liability or otherwise inconsistent obligations because of the absent party’s claimed interest in the subject matter of the litigation.”
[California Practice Guide: Civil Procedure Before Trial [citations to primary sources omitted]]
