XV. Half-brothers Roscoe and Salvio inherited from their father a vast tract of unregistered land. Roscoe succeeded in gaining possession of the parcel of land in its entirety and transferring the tax declaration thereon in his name. Roscoe sold the northern half to Bono, Salvio's cousin. Upon learning of the sale, Salvio asked Roscoe to convey the southern half to him. Roscoe refused as he even sold one-third of the southern half along the West to Carlo. Thereupon, Salvio filed an action for the reconveyance of the southern half against Roscoe only. Carlo was not impleaded. After filing his answer, Roscoe sold the middle third of the southern half to Nina. Salvio did not amend the complaint to implead Nina. After trial, the court rendered judgment ordering Roscoe to reconvey the entire southern half to Salvio. The judgment became final and executory. A writ of execution having been issued, the Sheriff required Roscoe, Carlo and Nina to vacate the southern half and yield possession thereof to Salvio as the prevailing party. Carlo and Nina refused, contending that they are not bound by the judgment as they are not parties to the case. Is the contention tenable? Explain fully. ( 4% )