For the purposes of § 10-45-96, the term, professional employer organization, means a firm which:
(1) Enters into a contractual agreement with a client company to create a co-employment relationship for the provision of payroll, benefits, and other human resources functions;
(2) Covers at least seventy-five percent of the client company's full-time or full-time equivalent employees domiciled in South Dakota; and
(3) Maintains separate books and records of account for each client company.