Inter-company Consignment Sale Process

here is the scenario...

Company A recvs orders frm cstmrs for nmbr of products, which are mfd by different companies of the same group.

Company A distributes these orders to respective Mfg Comapnies of the group ( Consignment order)

Products are mfgd and despatched against Consignment Order and Company A despatchs it to customers.

please guide me to map this in SAP with all respective modules(MM.. SD..??)

Please Note: MRP used for Finished goods planning at mfg plants only.