No renderer.enabled=false on grouped GameObject

Hi everyone,
if some of my Gameobjects are grouped in the hierarchy “GameObject.renderer.enabled = false;” is not working.
I just want hide some objects if the mouse is over an object. Is there anybody who can explain that to me?
Im still a beginner on Unity and in some points I dont understand the software. Here is my code snippet:

#pragma strict

var group1 : GameObject;
var group2 : GameObject;

function Start() {
 	group1 = GameObject.Find("GameObjectGroup1");
 	group2 = GameObject.Find("GameObjectGroup2");

function OnMouseOver() { = false; = true;

function OnMouseExit() { = true; = false;

it would be great if some of you have me some answers.

group1.GetComponent().enabled = false;

This should work. Or simply;

I believe the latter solution deactives the Collider and everything too though.

it works. thank you very much!
I just need more time to handle with unity;)