The undivided interest in the common elements shall not be separated from the unit to which it appertains and shall be conveyed or encumbered with the unit even though such interest is not expressly mentioned or described in the conveyance or other instrument.
Common Elements -- Undivided Interest To Remain Attached To Unit
Mont. Code Ann. § 70-23-404, under Nature of the Ownership Interest.
Mont. Code Ann. § 70-23-404