I'm trying to find a way to make a source create items (with two different itemtypes) based on the content of two conveyors that are downqueue (I also want to make the max content of these conveyors be 8 without changing the conveyor's length). For example, if a robot pulls an item with type 1 from a conveyor, I want a source to create another item with type 1 to send through the system in its place. The concept I'm trying to simulate is "build to buffer" if that helps clarify what I am seeking to do. Is there a way I could have the robot send a message to the source on what it is pulling and have the source create an item based on that? Thanks in advance