[xmonad] Determining layout based on display properties

Hello, I was wondering if there's a way to change the workspace layout based on the properties of the display (i.e., resolution). I'm trying to use a three column layout when my laptop is using an external monitor, but a two column layout when I'm using the built-in display. This doesn't have to be dynamic - if the workspace layouts are set once when xmonad is launched based on which monitors are in use, that would be fine. Thanks, Samir Unni