Changing a variable in another script for one object.

Ok, I already know how to change the variable in another script. All you do is this:

 GameObject.GetComponent(ScriptName).variableName +=1;

But my problem is I have to change the variable TestVariable located in one Gameobject, even though the script is in many gameobjects.

That Probably didn't make sense, so let me explain.

I have hundreds of game objects stored in a 3-dimensional array called "chunks", like this:

 static internal var chunks : GameObject[,,] = new GameObject[5,5,5];
 for(var z=0;z<chunktotal;z+=1) {
 for(var y=0;y<chunktotal;y+=1) {
 for(var a=0;a<chunktotal;a+=1) {
 chunks[x,y,z]=GameObject.Instantiate(chunkObject,Vector3(x,y,z),Quaternion.identity);

This creates 125 of the object "chunkObject". "chunkObject" is a GameObject that has the component "ScriptA" in it. So now lets say I want to change a variable in the script of of just one of the 125 gameobjects I created. Here is how Im currently doing it:

 chunks[0,0,0].GetComponent(ScriptA).testvar =1;

This code works. Except for one problem. Every single testvar in the objects stored in chunks[x,y,z] is changed. For example, running the code above would change all 125 gameobjects have testvar set to 1. Even though I specified which one I wanted to change! (In this case, chunks[0,0,0])

So does anyone know how to edit this code to change testvar of just one gameobject, not all 125?