Whenever it shall appear to the selectmen or assessors that 2 or more tracts of land which do not adjoin or are situated so as to become separate estates have the same owner, they shall appraise and describe each tract separately and cause such appraisal and description to appear in their inventory. In determining whether or not contiguous tracts are separate estates, the selectmen or assessors shall give due regard to whether the tracts can legally be transferred separately under the provisions of the subdivision laws including N.H. Rev. Stat. § 676:18, N.H. Rev. Stat. § 674:37-a, and N.H. Rev. Stat. § 674:39-a.