The commissioner may by rule define lines and classes of insurance which are not already defined under Section 31A-1-301. These definitions may be used for any purposes within the commissioner's regulatory power, including:
(1) providing instructions for reports and replies under Section 31A-2-202;
(2) controlling combinations of lines or classes of insurance; and
(3) determining which rules under Chapter 22, Contracts in Specific Lines, are applicable.