Change base material color instead of each individual object (js)

Hi,

I have a material which is applied to multiple objects (car parts) in my scene.
How can I change the color of this base material in js, resulting in all objects getting that same new color?

So instead of;

if(GUI.Button(new Rect (Screen.width - 270,650,240,240), btnOrange)){
		bonnet.renderer.material.color = Color(255/255.0F, 128/255.0F, 0/255.0F, 1);
		roof.renderer.material.color = Color(255/255.0F, 128/255.0F, 0/255.0F, 1);
	}

i.e. changing the material color for each object (bonnet, spoilers, roof etc.), I’d like to change al of these in one go.

Any help would be appreciated, better ways of doing this included.

take a look at this : http://answers.unity3d.com/questions/228744/material-versus-shared-material.html

Thanks PAEvenson, I’ll have a look at that to understand material concepts a bit better.

In the meantime, I figured it out by using an extremely obvious method which I thought I already tried.

var targetMaterial : Material; 

if(GUI.Button(new Rect (Screen.width - 270,650,240,240), btnOrange)){
		targetMaterial.color = Color(255/255.0F, 128/255.0F, 0/255.0F, 1);
	}

Which works perfectly and seems pretty solid.