Start Texture Animation when object is unhidden

I've got two boxes. Each has a different movie assigned to it as a texture. The first movie starts automatically, since I have the following code attached to it, which is not applied to the 2nd box:

     function Update () {
 renderer.material.mainTexture.Play();
 }

The 2nd box starts out hidden, and then I click a button to unhide it, and hide the first box. Here's the code for that:

 var customButton: GUIStyle;
 var Military: GameObject;
 var Mainscreen: GameObject;
 
 
 function Awake () {
         Military = GameObject.FindWithTag("CubeMilitary");
         Military.renderer.enabled = false;
 }
 
 
 
 function OnGUI () 
 {
     if( GUI.Button( Rect( 485, 210, 177, 40 ), "Here", customButton ))
     {
         Mainscreen = GameObject.FindWithTag("CubeInterface");
         Mainscreen.renderer.enabled = false;
         Military = GameObject.FindWithTag("CubeMilitary");
         Military.renderer.enabled = true;
         
     }
 }

My problem is that I want to be able to cue the 2nd movie texture to start playing as soon as the 2nd box is unhidden. I'm not sure exactly how to implement that within the on GUI function, or even if that is the best method. Any ideas?

Thanks.