Multiple router devices with a single coordinator setup

Hello guys, I would like to ask for advice on how to code my microcontroller (nodeMCU esp-12) to turn ON/OFF digital pins of the remote router devices using a single coordinator device.

I have followed this guide and I was able to test it with 1 coordinator and 1 router. Now I would like to add another router device to the network. I was not able to find enough information on how to do that. Any help is appreciated

/code by tunnelsup
//youtube tutorial: https://www.youtube.com/watch?v=CzH146rR-7I
//toggles local LED and remote XBee LED on and off

int led = 13;

void setup(){
  pinMode(led, OUTPUT);
  Serial.begin(9600);
}

void loop(){
  digitalWrite(led, HIGH);
  setRemoteState(0x5);
  delay(5000);
  digitalWrite(led, LOW);
  setRemoteState(0x4);
  delay(5000);
}

void setRemoteState (char value){
  Serial.write(0x7E); //start byte
  Serial.write((byte)0x0); //high part of length (always zero)
  Serial.write(0x10);  //low part of length
  Serial.write(0x17); //0x17 is remote AT command
    Serial.write((byte)0x0);  //frame ID set to zero for no reply

  //ID of recipient, or use 0xFFFF for broadcast
  Serial.write((byte)0x0);
  Serial.write((byte)0x0);
  Serial.write((byte)0x0);
  Serial.write((byte)0x0);
  Serial.write((byte)0x0);
  Serial.write((byte)0x0);
  Serial.write(0xFF);
  Serial.write(0xFF);
  
  //16 bit of recipient of 0xFFFE
  
  Serial.write(0xFF);
  Serial.write(0xFE);
  
  Serial.write(0x02);
 
  Serial.write('D');
  Serial.write('4');

 
  //command data in as many bytes
  Serial.write(value);
  
  //checksum
  long sum = 0x17 + 0xFF + 0xFF + 0xFF + 0xFE + 0x02 + 'D' + '4' + value;
  Serial.write(0xFF - (sum & 0xFF));
}