Ring only allows one Amazon Key Lock to be registered?

I just bought 4 Schlage Encode WiFi deadbolts, and I would like to connect them to Ring and Ring Alarm.

Unfortuantely it seems there is only one way to do it (through the Amazon Key app) and even then, I can only pick ONE of my locks to be integrated.

Why can’t I fully integrate all 4 of my wifi smart locks with Ring and Ring Alarm?