Any of the districts enumerated in Chapter 19.12, except the U district or the AG district, may be combined with any other district or districts; except that no R district shall be combined with any M district, nor shall any R-1 district be combined with any district other than another R district, or a B district.

When two or more districts are so combined; the regulations for any use proposed in the resulting combined districts shall be the regulations set forth in. Sections 19.24.020 and 19.24.030 for the proposed use, as if the districts were not combined.