Premium taxes and taxes on premiums paid for coverage of risks resident or located in this state by a purchasing group or any members of the purchasing groups must be:
(1) Imposed at the same rate and subject to the same interest, fines, and penalties as those applicable to premium taxes and taxes on premiums paid for similar coverage from authorized insurers, as defined under chapter
48.05 RCW, or unauthorized insurers, as defined and provided for under chapter
48.15 RCW, by other insurers; and
(2) The obligation of the insurer; and if not paid by the insurer, then the obligation of the purchasing group; and if not paid by the purchasing group, then the obligation of the insurance producer for the purchasing group; and if not paid by the insurance producer for the purchasing group, then the obligation of each of the purchasing group's members. The liability of each member of the purchasing group is several, not joint, and is limited to the tax due in relation to the premiums paid by that member.