To 'do it right'/weather-resistant would require some thinkin,,,,

Could it be done? Sure. One way might end up with 'mini' compartments with the hinges located just above the suspension. Kind of a 'how bad do you want it?' situation that would change the appearance of the otherwise smooth one piece lids.

But,,,,, How difficult is it to remove the lids as-is? (I assume the lids currently connect along the bottom perimeter of the axle well w/bolts - screws? )

If nothing else,,,,, perhaps the bottom edge of the lids could be made with a tang to drop in a slot,,,, just enough pivot to release OEM latches, swing top of lid out a little, pick up to remove entire lid, (and then watch your stuff fall out on ground,, LOL!)

Sealing/rattles/ and structural reinforcement of the lids would have to be addressed,,, Fun to think about!