Advice on Wiegand Buffer

Hi i'm trying to integrate a wiegand keypad into an access control board that only accepts wiegand card reader inputs (+ 26 bits long) and the keypad sends 4 bits with each key press which is assumed to be a bad card read by the board. I was thinking that I could make a buffer to receive 4 bits at a time until the sixth key press and then forward them all at once to the access control board.

If anyone could offer some advice on this, if it would be easy, worth while, where to start it would be much appreciated.

Thanks