A Radio Frequency Identification (RFID) system that tracks tags in real-time based on EPC codes and on other priority codes written into transponder memory fields of the tags. As an example, a priority code may be written into a memory of an RFID transponder identifying a high-value item or a small high-value item that is likely to be stolen. Based on the use of this priority code, those items can be preferentially tracked as opposed to items of low value or size such that they are unlikely to be stolen. Such use of priority codes and local filtering alleviates the need to go back to large centralized databases associating unique numbers with other parameters and potentially the history of the item.