As used in ORS 237.420 to 237.510, unless the context requires otherwise:
(1) “Public agency” or “political subdivision” means the State of Oregon, any city, county, municipal or public corporation or any political subdivision of the State of Oregon or any instrumentality thereof, or any school district, or any agency created by two or more political subdivisions to provide themselves governmental services, the employees of which constitute a coverage group. For purposes of ORS 237.420 to 237.510, such agency created by two or more political subdivisions is a governmental instrumentality and a legal entity with power to enter into contracts, hold property and sue and be sued.
(2) “Coverage group” has the meaning given that term by the provisions of section 218 of title 2 of the federal Social Security Act, and amendments thereto, and applicable federal regulations adopted pursuant thereto.