Serial Type

I wrote a library for an LCD screen that I have and I want to expand dynamically. I have an Arduino Mega 2560 board, and inherently, 4 different serial TX ports accessed via Serial, Serial1, Serial2, and Serial3. Currently I have the library hard coded to use Serial1, which is fine for this project, but how would I go about passing type Serial to the library? Example:

#include <LCD.h>

LCD lcd1;
LCD lcd2;
LCD lcd3;

void setup()
{
  lcd1 = LCD(Serial);
  lcd2 = LCD(Serial1);
  lcd3 = LCD(Serial3);
}

void loop()
{
  lcd1.printToLCD("This screen uses Serial on pin 1");
  lcd2.printToLCD("This screen uses Serial on pin 18");
  lcd3.printToLCD("This screen uses Serial on pin 14");
}

Basically, what Class or type are variables Serial, Serial1, Serial2 and Serial3?

Thanks,
Stauffski

Serial, Serial1, Serial2, and Serial3 are all instances of the HardwareSerial class.

Thank you much good sir!