Hi I have two suggestions for you
1- at this point you can link the 7 receivers using modbus as slaves to a master webserver esp32.
2- you could also use esp wifi mesh then link one node to the webserver esp using serial communication
I have expertise in
Electronics/embedded systems
PCB layout design, circuit design, embedded systems design, Arduino, ESP32,STM32, PIV, AVR
CAD/CAM
Altuim, Eagle, EasyEDA, Proteus, Kicad
Programming languages
C/C++, C#, WPF, Xamarin
Firmware technology
IoT, Bluetooth classic, Bluetooth BLE, WiFi Portals, GSM, Webserver/socket, HMI displays,...
Platforms/ IDE
Arduino IDE, PlatformIO, Visual studio, visual studio code, MPLABx, AVR Studio, MikroC for PIC.