ESP8266 Community Forum

The host or central device broadcast a message string, which after connecting with the host device can be checked at the both other ESP Devices and there is a condition set on both clients, if the string matched with first client, then you can set states of GPIO pins of client device.

I would like to recommend EFB-IoT by SSLA. This product might help you to achieve your target. Do have a look.

https://www.ssla.co.uk/product/esp32-evaluation/