Where all the crofters interested in a common grazing shall have signed a condition or conditions regulating the use of the same, and the Crofters Commission shall have found or shall find such condition or conditions to be reasonable, as provided by section one, sub-section five, of the said principal Act, such condition or conditions may be recorded and enforced in like manner as if they were regulations made in terms of this Act and approved of by the Crofters Commission.