In this video you can find how to group several Sales Orders (SO) from different clients for the same product into 1 Manufacturing order (MO) without losing the traceability afterwards of the ordered quantities for each client. 

FYI : This method also works with Purchase Orders (PO)->Check that  the "propagation of procurement group" is set to "Propagate" on the Buy route

The main steps are:

1) Define a reordering rule 0/0 with trigger= manual in the replenishment view (preferred route manufacturing) of the Inventory app for your manufactured product

        -->Each confirmed Sales order will generate or update the line for the manufactured product in the replenishment view

2) Click on “order once” in the replenishment view when you want to generate the  Manufacturing order

        --> The confirmed Manufacturing Order will group the requested quantities from the different SO’s

        --> The produced quantities will automatically be reserved on the deliveries (WH/OUT) of the linked Sales Orders 

screenshots video:

Confirmed Sales orders

Replenishment view

Generated Manufacturing Order

Product Moves/reserved quantities on delivery (WH/OUT)