This problem can be solved with the use of air springs. Firestone Industrial Products Company is the maker of the RideRite™ Air Helper Springs, air springs that mount to the existing suspension components of the vehicle and allow you to control the carrying capacity by just changing the air pressure inside the springs, preventing suspension “bottom-out” and preserving a natural ride height.
The specific RideRite air helper spring for the Jeep Commander is part number 4157. You will also need the accessory kit, which contains among other things an air compressor and an in-dash control panel. The accessory kit comes in two versions: single ( part number 2158, for normal applications – same air pressure in both springs) and dual (part number 2178, independent air pressure control for each spring, for off-centered loads).