I'm a bit confused by the description of the situation myself, but the rule of thumb is a linear submission process.
Raw Material(s) --> Processor --> Assembler --> Customer
Each submits to their customer. In the quickie example here, the Raw Material Supplier(s) provides PPAP to the Processor, their customer, and the Processor(s) would submit their PPAP (and, if required, the Raw Material Supplier's PPAP) to the Assembler who would, as the Assembler, have their own PPAP package to submit to the Customer. It's a 'chain' scenario.