Serial Port cannot get data sometimes during start up

General
1

I have 3 arduino running with USB at 115200 bps. When I start my computer, I see the three serial nodes are labelled connected. But sometimes, I don't see any data from one or two port during startup. I need to unplug and plug the USB several times to restart the data transfer.
My data is like this 111,222,333,444,555,666,777,/n And the data packet rate is 1Hz only.

And I also think may be the arduino does not have enough power, so I add external 5V to one of the board. No lucky.

Is there any setting I can try in the serial port node?

My Arduino code is simple
void setup() {
Serial.begin(115200);
}
void loop() {
...delay
Serial.println(xxx);
}

I saw in a website (https://arduino.stackexchange.com/questions/439/why-does-starting-the-serial-monitor-restart-the-sketch) says
" The Arduino uses the RTS (Request To Send) (and I think DTR (Data Terminal Ready)) signals to auto-reset."

Can I trigger the RTS in the serial port node?

Thanks