Tsundraki

Is it possible if you position a unit of Droidekas in a certain way for the unit to give itself cover? If you have one model behind the other does the LoS blocking for ground vehicles apply when checking if the second model has cover? If 50% of the back model is blocked that would give the back model heavy cover which is 50% of the unit. It feels like I'm missing something here that would make this not work, so I wanted to verify. Thanks!