Link Horizontal Sliders?

I need help linking horizontal sliders, For example.

In my main menu, when i click options a slider comes up and controls the volume, And then when i click play and i pause the game and click options a slider pops up and has the same ammount as the slider in the main menu, Understand? no okay, In slender: The Arrival in the main menu you control the volume and when you go in game and look at the volume its the same as the main menu.

Here is my script:

 var hSliderValue : float = 1.0;
 
 function OnGUI(){
     hSliderValue = GUI.HorizontalSlider (Rect(25,25,100,30), hSliderValue, 0.0, 1.0);
     AudioListener.volume=hSliderValue;
 }

I need that to sync with another slider. any suggestings?