Class Instance - Create specific count of instance only - Multithreading environment

Like for Singleton pattern, we manage and create only 1 instance.

now for suppose class Abc, i just want to

1.) create only 3 instances at maximum.

2.) Multithreading environment.

class Abc{
  private static Abc abc1;
  private static Abc abc2;
  private static Abc abc3;

private Abc(){

}

 public static synchronized Abc getInstance1(){
        if(abc1 == null){
            abc1 = new Abc();
        }
        return abc1;
    }

: // same as above for abc2
: // same as above for abc3

}

** Now problem is suppose i want to increase instance from total 3 to to say 4 or 5 or n number.

Also i do want to expose so many methods (getInstance1(), getInstance2()... etc)