(b) As a traveling or city salesman, other than as an agent-driver or commission-driver, engaged upon a full-time basis in the solicitation on behalf of, and the transmission to, a principal (except for sideline sales activities on behalf of some other person) of orders from wholesalers, retailers, contractors, or operator of hotels, restaurants, or other similar establishments for merchandise for resale or supplies for use in their business operations. However, for purposes of this subsection, the term "employment" shall include services described in paragraphs (2)(a) and (b) of this subsection, only if:
(i) The contract of service contemplates that substantially all of the services are to be performed personally by such individual;(ii) The individual does not have a substantial investment in facilities used in connection with the performance of the services (other than in facilities for transportation); and(iii) The services are not in the nature of a single transaction that is not part of a continuing relationship with the person for whom the services are performed.