Calling numbers simultaneously

Question

I provided a code that calls a specific number upon executing and uploading it to the microprocessor. I want it to call five different numbers simultaneously at a period of time(3 minutes).

#include <SoftwareSerial.h>
SoftwareSerial sim(10, 11);

// Define an array of phone numbers
String numbers[] = {
  "+639*********",  // Change with your first number
  "+639*********",    // Change with your second number
  "+639*********",    // Change with your third number
  "+639*********",    // Change with your fourth number
  "+639*********"     // Change with your fifth number
};

int selectedNumber = -1; // Index of the selected number, initially set to -1
int ledPin = 9; // Define the LED pin

void setup() {  
  Serial.begin(9600);
  Serial.println("System Started...");
  sim.begin(9600);
  pinMode(ledPin, OUTPUT); // Set the LED pin as an OUTPUT
  digitalWrite(ledPin, LOW); // Initially turn off the LED
  delay(1000);
  Serial.println("Type a number (1-5) to call the corresponding contact");
}

void loop() {
  if (Serial.available() > 0) {
    char input = Serial.read();
    int numericInput = input - '0'; // Convert the character to an integer
    if (numericInput >= 1 && numericInput <= 5) {
      selectedNumber = numericInput - 1; // Adjust to 0-based index
      callNumber();
    } else {
      Serial.println("Invalid input. Type a number from 1 to 5 to call a contact.");
    }
  }
}

void callNumber() {
  if (selectedNumber >= 0 && selectedNumber < 5) {
    sim.print(F("ATD"));
    sim.print(numbers[selectedNumber]);
    sim.print(F(";\r\n"));
    digitalWrite(ledPin, HIGH); // Turn on the LED when making the call
    delay(1000); // Call will last for 2 minutes (1000 milliseconds)
  }
}