Hi Amar
"I want to know what setting should be done so that MRP in plant B should consider the demand qty from Plant A i.e 100 nos.And PR created in plant B should have linkage wrt to PR Qty from plant A"
There is no setting in plant B as such. In my experience you need to run MRP regularly in Plant A with an standard MRP type (PD) so you have stock transport requisitions representing the demand from plant A in the stock requirements list for plant B. Note reorder point planning in plant A doesn't really work.
Creating a link between the requirements at different levels in the supply chain doesn't really work either. Things will change down in plant A which will result in changes to the stock transport requisitions which will make a mess of any relationships to purchase orders raised by plant B.
Regards
Robyn