Use only user defined modes -- possible?

[Not so pretty now]

Nvidia driver has an option for this called "ModeValidation", is ati driver capable of something similar?

I would like to use these modes only:

SubSection "Display"
	Viewport   0 0
	Depth     24
        Modes    "1920x1080" "1280x960" "800x600" "960x540" "640x480"
EndSubSection