I want to realize this function: 1. When Queue2 is empty, move object from Combiner1 to Queue2. 2. When Processor1 is available, move item (box) from pallet of Queue2 to processor1. 3. When item(box) on pallet of Queue2 is empty, move pallet from Queue2 to Sink1. How to realize it with processflow, Can you help me?