SwitchResX includes a function to remove a display from the System's list of managed display. This means the display in question, once deactivated, will not be visible from the System or from any application. Only SwitchResX will be able to activate the display again.
To get this option active, open the Preferences application, go in the "Menus" section, select "Enable/Disable displays" and you'll get the option in one of the SwitchResX menus
Please also note that if you have mirroring enabled, the menu item will NOT show. So be also sure to disable video mirroring.
There are however some compatibility problems on Yosemite and Mavericks: see this
section of the FAQ.