Subject to § 8.01-286.1, if an unincorporated (i) association, (ii) order, or (iii) common carrier has its principal office outside Virginia and transacts business or affairs in the Commonwealth, process may be served on any officer, trustee, director, staff member, or agent of such association, order, or carrier in the city or county in which he may be found or on the Clerk of the State Corporation Commission, who shall be deemed by virtue of such transaction of business or affairs in the Commonwealth to have been appointed statutory agent of such association, order, or carrier upon whom may be made service of process in accordance with § 12.1-19.1. Service, when duly made, shall constitute sufficient foundation for a personal judgment against such association, order, or carrier. If service may not be had as aforesaid, then on affidavit of that fact an order of publication may be awarded as provided by §§ 8.01-316 and 8.01-317.