Control the distance between populated points

Hello! I would like to control the distance between two populated points to be these three specific length only; 6,9,12 so that I can have all the line segments between points with these specific size. I tried creating all the lines first and then selected only the desirable one but it turns out as one member only. So I am wondering if there is any way I can control the distance between points to be these three numbers only BUT randomly from the beginning?