In the attached model (8778-multi-cylinder-combiner-jv-2.fsm) a single combiner is able to build three different sets of product. It is also able to put a delay as each cylinder enters the combiner (thank you @Jörg Vogel!).
The last piece of the puzzle for me is visual. Does anyone know of a way to change the visuals on the combiner such that the product "grows" as items are added? So as a simplified example you'd start with cylinder #1, then when cylinder #2 is added the item shown on the combiner doubles in size. When cylinder #3 is added the size is three times the original. This continues as you add cylinders until the product is complete.