In the attached model, I have 10 combiners in a series that represent 3D printers. AGVs deliver 3 items to every combiner to process. The customer wants to have Combiner #1 to receive all 3 items so it can start processing before Combiner #2 gets its first item. So then Combiner #2 would get its 3 items and start processing and further down the line.
The same thing would happen in reverse. When Combiner#1 is finished, the AGVs would prioritize unloading all 3 items from Combiner #1, re-loading combiner #1 with 3 new items so it can restart printing. Then the AGVs support any other combiners.
I'm not sure how to implement this logic. Any help would be appreciated.