One RFID i connected like this:
RFID Mega
* RST/Reset 6
* SPI SS 7
* SPI MOSI 51
* SPI MISO 50
* SPI SCK 52
*
I tried connect second RFID in the same way, using this same reset pin, but changing SPI SS pin to 8 using the example of library MFRC522 ReadUidMultiReader, but didn't work (program can't find any RFID reader).
I have no idea how it connect, so i don't have any schematic.