Tag collisions can impose a major inefficiency in RFID systems, resulting in low identification rates, short reading range and ineffective resource utilization. They are more problematic in passive tags due to limitations on power and functionality. In this paper, we present a novel approach to overcome the passive tag collision problem. The novelty in our scheme is that it requires no additional memory, results in a higher identification rate and reduces power and medium consumption. The proposed scheme can be augmented to tree-based anti-collision proposals, both existing and to come, and substantially improve their performance. Performance results indicate that the augmented schemes bear significant gains that are achieved by reducing collision, overhead and delay.