When the jurisdiction of the district court is based in whole or in part upon section 1369 of this title, process, other than subpoenas, may be served at any place within the United States, or anywhere outside the United States if otherwise permitted by law.
28 U.S. Code § 1697 - Service in multiparty, multiforum actions
(Added Pub. L. 107–273, div. C, title I, § 11020(b)(4)(A)(i), Nov. 2, 2002, 116 Stat. 1828.)