Fed. R. Civ. P. 20

(a) PERSONS WHO MAY JOIN OR BE JOINED.

(1) Plaintiffs. Persons may join in one action as plaintiffs if:

(A) they assert any right to relief jointly, severally, or

in the alternative with respect to or arising out of the

same transaction, occurrence, or series of transactions or

occurrences; and

(B) any question of law or fact common to all plaintiffs

will arise in the action.

(2) Defendants. Persons—as well as a vessel, cargo, or other

property subject to admiralty process in rem—may be joined

in one action as defendants if:

(A) any right to relief is asserted against them jointly,

severally, or in the alternative with respect to or arising

out of the same transaction, occurrence, or series of transactions or occurrences; and

(B) any question of law or fact common to all defendants

will arise in the action.

(3) Extent of Relief. Neither a plaintiff nor a defendant need

be interested in obtaining or defending against all the relief

demanded. The court may grant judgment to one or more

plaintiffs according to their rights, and against one or more

defendants according to their liabilities.

(b) PROTECTIVE MEASURES. The court may issue orders—including an order for separate trials—to protect a party against embarrassment, delay, expense, or other prejudice that arises from including a person against whom the party asserts no claim and who

asserts no claim against the party.

(As amended Feb. 28, 1966, eff. July 1, 1966; Mar. 2, 1987, eff. Aug.

1, 1987; Apr. 30, 2007, eff. Dec. 1, 2007.)