Hi ,
There is a config under Prod--> DRP-->Basic setting-->Main assignment of node type-plant. here you can define Plant as B-Distribution center. There is no significance of this config.
Since you need plant to hold stock , Distribution center will be a plant object with node type defined in above config( Or you can implement MRP area , if you donot want to create more plants)
Either way ,
You have setup stock trasnfer between Plant(DC) & Plant using special procurement type(F-40) & system will generate Stock transfer PR which can be converted in Stock transfer PO
You can set up multiple key 41,42,43,44 for each plant(DC) pointing to differenet plant(Mfg)You can use this key in material master of Plant (DC) to define which plant will supply this material.
SAP MRP run is also deployment , it will plan Stock transfer PR based on demand entered on Plant(DC)
Hope it helps,
Jatin