The ESP8266 API we use in the firmware only depends on the SSID name and password. If all three routers have the same SSID name, it’s not entirely clear to me how it decides which one to connect to. What kind of network arrangement do you have with the three routers? Are two of them repeaters or something like that? There has to be some way that they are aware of each other, right? Otherwise how does routing working, when a device from one router tries to reach another device connect to another router?