[xmonad] How to configure TwoPane to this way

Hi All, I like the TwoPane layout, but need to special configuration: Suppose we have windows A, B and C. Now A is on left pane and focused, B is on right pane, C is not visible: (A) | B, C Now I need a special HotKey, when triggered, it keeps B untouched, just switch between A and C on the left pane. And I also want another HotKey to switch between left and right pane. Is that doable? I need it a lot, thanks very much. best lars