Res Judicata

Q. A filed a civil suit for ejectment and arrears of rent against B,C and D, alleging that his tenant B was in arrears of rent court decreed the suit for arrears of rent and C and D were his sub-tenants. Only C and D contested it. Trial court decreed the suit for arrears of rent against. It was held that C and were not sub-tenants. Only B filed appeal which was dismissed but the appellate court while observing that any evidence led by C and could not be read against B further observed that it appeared that c and D being closely related to B were in possession on his behalf. A filed second civil suit for ejectment and arrears of rent now pleading, interalia, that C and D were licensees of B and that the judgment of the appellate court in earlier case will operate as res-judicata. Is the plea of A about res judicata correct? Give reasons for your view?