Civil Code § 3433

Where a creditor is entitled to resort to each of several funds for the satisfaction of his claim, and another person has an interest in, or is entitled as a creditor to resort to some, but not all of them, the latter may require the former to seek satisfaction from those funds to which the latter has no such claim, so far as it can be done without impairing the right of the former to complete satisfaction, and without doing injustice to third persons.