Terrain type - Cave

[Starmyth]

Is it possible or desirable to create a terrain or 'kit' type 'cave'? This should be very similar to bunkers for concealing troops. Caves should be even more difficult to find than bunkers and would be excellent for concealing troops. Caves would be available free. Caves would be relatively common in mountains and quite rare in deserts. This might be a difficult or impossible concept for the AI to handle. Blitzkreig vs Sitzkreig.