What compensation is due if one person is promised a specific amount for returning an item, while others are promised an unknown amount, and they return it together?

Primary text

If one person is promised one Dinar for the return, and two others are promised an unknown compensation, and they return it together, the person promised the Dinar receives the full Dinar. The other two individuals are entitled only to the wage for their labor, as their promised compensation was indeterminate.