All appeals are dismissed.

The costs of appeal are assessed against the Defendants.

The grounds of appeal are examined.

1. As to the assertion regarding preferential repayment right and satisfaction right of joint collateral security

A. (1) In cases where a joint mortgagee has been apportioned part of the secured debt out of the proceeds from the sale of part of the immovable property, which is the object of joint collateral, through the realization procedure of auction, etc. conducted by a third party, the joint mortgagee cannot exercise the right to preferential reimbursement as a joint mortgagee again in the realization procedure of the remaining object of joint collateral (see, e.g., Supreme Court en banc Decision 2013Da16992, Dec. 21, 2017). This legal doctrine applies to cases where a joint mortgagee sells the immovable property owned by the debtor to a third party and performs part of the secured debt in return for the sale of the immovable property, i.e., the joint mortgagee cannot exercise the right to preferential reimbursement for the sole reason that the joint mortgagee would not exercise the right to preferential reimbursement during the realization procedure of the immovable property, which is the object of joint collateral, by means of a voluntary method of realizing the secured debt.