I have an oven that can take different items as long as they are run at the same specified temperature. Each item has a different dimension, therefore the capacity of each item within the oven varies. Example, Item A has a maximum capacity of 100, Item B has a maximum capacity of 50, and Item C has a maximum capacity of 30. I have 50 units of Item A, 10 units of Item B, and 6 units of Item C. All are allowed to go into the oven together as they run at the same temperature. In this scenario, Item A is 50% (50/100) of the oven, Item B is 20%(10/50) of the oven (10/50), and Item C is 20% (6/30) of the oven. Oven is at 90% capacity. How can I model this in Ortems PS?