If there's an unusual keycode you need to start the process, maybe you could encode it into the start of the RFID string on the tag. Or maybe RFID readers are

If there's an unusual keycode you need to start the process, maybe you could encode it into the start of the RFID string on the tag. Or maybe RFID readers are configurable like the barcode scanners I've worked with and you can program them to emit the keycode as a prefix.