Discontinuation functionality with production orders

Dear Guru's,

Can anyone please confirm: is the functionality for discontinuation of a material (including follow-up material) not available with production orders?

Example: in our system we have component A that is followed up by component B. This is set in material master - MRP 4.

We also have production orders for the upcoming 4 months in our system. If the stock of component A is depleted within these 4 months, we would expect to see requirements (orderreservations?) on component B, but this is not the case.

Thanks for any comments,

Rgds, AJ