As used in this chapter, the term "employing unit" means any individual, the legal representative of a deceased individual, or any type of organization, including any partnership, association, trust, estate, joint-stock company, insurance company, or corporation, whether domestic or foreign, employee leasing company, common paymaster, or the receiver, trustee in bankruptcy, trustee, or successor thereof which has or had in its employ one or more individuals performing services for it within this state. Each individual performing services within this state for any employing unit which maintains two or more separate establishments within this state shall be deemed to be employed by a single employing unit for all the purposes of this chapter. Each individual employed to perform or to assist in performing the work of any agent or employee of an employing unit shall be deemed to be employed by such employing unit for all the purposes of this chapter, whether such individual was hired or paid directly by such employing unit or by such agent or employee, provided the employing unit had actual or constructive knowledge of such work.