Ohio Rev. Code § 2703.29: Service of summons on cross petition upon nonresident plaintiff.

When a plaintiff is not a resident of the state and a defendant files a cross petition, service of summons on the cross petition may be made upon such nonresident plaintiff by registered mail directed to the plaintiff at the address listed by plaintiff with the clerk of courts of the county in which the action is pending and the return of the sheriff shall be in accordance with section 2703.23 of the Revised Code.

Thereafter continued prosecution of the case by the nonresident plaintiff shall be deemed a waiver of service of summons on the cross petition.