A co-owner of a thing may exercise the right of redemption in case the shares of all the other co-owners or of any of them, are sold to a third person. If the price of the alienation is grossly excessive, the redemptioner shall pay only a reasonable one.
Should two or more co-owners desire to exercise the right of redemption, they may only do so in proportion to the share they may respectively have in the thing owned in common. (1522a)