How to hide TVs from certain users

I need to have some TVs on pages to add functionality but don't want certain users to be able to see them in the control panel (throught the Template Variables tab of the resource). How do I go about hiding TVs from lower level users but not the admin?

Thank you in advance.

Revo 2.1.3
PHP Version 5.2.10

Do you already have permisions set for certain groups or users?

If not a good place to start could be here:

http://rtfm.modx.com/display/revolution20/Permissions

BobRay has a great tut on his site as well.

This is the relevant tutorial: http://bobsguides.com/hiding-elements-in-the-manager.html

Thank you, everyone! Works great.