Palletizing unsolved problems

Hello guys,

I need some help with my simulation. I will explain you the entire process: So, my robot is picking and placing boxes from a conveyor to another conveyor on an euro-pallet. This job is done, but after every 3 layers, I need to pick an intra-layer and place it on the entire row of boxes. I couldn’t do that process. Could you explain me how should I do that?