You will need a Mapped Key with 2 Steps, set to execute when "pressed OR released". It doesn't need a Hotkey. In the first step, turn your special key maps on (Key Map State Action, or Mapped Key State Action), and in the second step turn them off. You can make it toggle on or off whatever you want, but this will get you started

Then create a new Repeater Region (because you can't just edit the existing one, X the old one out), and as you create it there is drop-down boxes to pick a Key Map and Mapped Key. It will "hold" this mapped key while the mouse is in the region, performing the first step when you enter (turning on your special key map), and the second when you exit (turning it off).