N.M. Code R. § 13.14.9.41
In the event a proposed insured requests that a single policy be issued insuring multiple New Mexico properties that may be located in more than one county, the amount of insurance shall be allocated to each county based upon a supported amount as provided in writing by the proposed insured. The premium shall be calculated as if a policy was being issued separately in each county and the aggregated gross premiums shall be combined to determine the gross premium for the single policy. A New Mexico title insurance agency or title insurer that maintains a title insurance agency or direct operation in one of the counties in which the property is located ("direct operation") (collectively "issuing company") must issue the policy and disburse, or direct the payee to disburse, the gross premium attributable to each county to the title insurance agency or direct operation in such county for such policy to be remitted to the title insurer in accordance with the division of premium rule in affect at the time of issuance. The policy schedules applicable to the land located in each county shall be countersigned by the title insurance agency or direct operation and provided to the issuing company. The issuing company shall provide each title insurance agency or direct operation with a complete copy of the final policy which shall be maintained in accordance with underwriter and regulatory requirements. Each title insurance agency or direct operation shall report the policy utilizing the combined policy number but only the gross premium it received attributable to the property within its county shall be reported. Issuance of a single policy shall not be used when the transaction involves property outside of New Mexico. This rule shall not be interpreted to allow a title insurer to issue what is commonly referred to as home office issued policies.
N.M. Code R. § 13.14.9.41