Wyo. Stat. § 1-6-105: Proceedings when defendants not all served.

(a) When service has been made on one (1) or more defendants, but not on all, the plaintiff may proceed as follows:

(i) If the action is against defendants jointly indebted upon contract, he may proceed against the defendants served, unless the court otherwise directs; or

(ii) If the action is against defendants severally liable, he may without prejudice to his rights against those not served, proceed against the defendants served.