Rule 19. Necessary joinder of parties.
(a) Necessary joinder. - Subject to the provisions of Rule 23, those who are united in interest must be joined as plaintiffs or defendants; but if the consent of anyone who should have been joined as plaintiff cannot be obtained he may be made a defendant, the reason therefor being stated in the complaint; provided, however, in all cases of joint contracts, a claim may be asserted against all or any number of the persons making such contracts.
(b) Joinder of parties not united in interest. - The court may determine any claim before it when it can do so without prejudice to the rights of any party or to the rights of others not before the court; but when a complete determination of such claim cannot be made without the presence of other parties, the court shall order such other parties summoned to appear in the action.
(c) Joinder of parties not united in interest - Names of omitted persons and reasons for nonjoinder to be pleaded. - In any pleading in which relief is asked, the pleader shall set forth the names, if known to him, of persons who ought to be parties if complete relief is to be accorded between those already parties, but who are not joined, and shall state why they are omitted. (1967, c. 954, s. 1.)