Mo. Rev. Stat. § 524.100: One or more joint plaintiffs may recover.

Where there are two or more plaintiffs, any one or more may recover any interest they may be entitled to, in the same manner as if they had brought separate actions; and it shall not be any objection to a recovery in such action that any one or several of the plaintiffs do not prove any interest in the premises claimed, but those entitled shall have judgment, according to their rights, for the whole or such part or portion as they might have recovered if they had brought separate suits.