California Code, Code of Civil Procedure - CCP § 347

If there is more than one such mortgagor, or more than one person claiming under a mortgagor, some of whom are not entitled to maintain such an action under the provisions of this Chapter, any one of them who is entitled to maintain such an action may redeem therein a divided or undivided part of the mortgaged premises, according as his interest may appear and have an accounting, for a part of the rents and profits proportionate to his interest in the mortgaged premises, on payment of a part of the mortgage money, bearing the same proportion to the whole of such money as the value of his divided or undivided interest in the premises bears to the whole of such premises.