Question on Demantra and ASCP Supply demand Consumption

We have global forecast from Demantra which is sent to ASCP , our requirement is ASCP should consider and map supply (only onhand ) which is across different orgs for that global forecast demand .

we have production plant in China where we do all the manufacturing and Sales orders and Forecast is also created to this factory .

But we have a Distribution center in Hang Kong where all the returns goods are collected . So we wanted to implement a Global FIFO LOGIC , Where the Sales Orders are first netted against the return goods in Hang kong , this is handled in Order management using a custom logic .