Central Procurement how to create both requisition and Purchase Order in purchasaing OU for Reciving

Hello Team,

We have a business scenario where there are two Operating Units say OU1,OU2 and OU3. Business would like to utilize the standard central Procurement functionality with OU1 and OU2 as central Procuring Organizations for OU3. Meaning OU1 and OU3 will be procuring on behalf of OU3 and OU3 will be receiving the items from vendor directly.

Could you please help me in understanding the central procurement functionality if OU1 and OU2 can create requisitions and convert the requisitions into Purchase orders automatically within OU1 and OU3 and have the line level warehouse on the requisition and purchase order to be of OU3 warehouse, so the OU3 can receive the items.