@reindier Please add some more info on your setup. In general, an ESP8266-based node is only intented to be a gateway (also other hardware con be chosen). Possibilities about using more than one gateway depend on the controller software you intend to use. Some support it, but could have additional restrictions. In general, I'd never use a multiple NodeMCU-setup with sensors directly attached to this MCU type the "MySensors"-way but instead use standard (especially MQTT) options for them (outside MySensors). So what means "arduino" on your setup? Just the Arduino IDE for programming the ESP8266's? If it's really ATMega328 MCU's, I'd go for other transport layers than regular WiFi (eg. use RFM69 transceivers).