Turning off MRP on items within a BOM but not on all BOM's

I am looking for a way to turn off MRP on certain items within a bill of material, but not necessarily on that item for all bill of materials. We sometimes purchase the material for some products and sometime the material is purchased by a subcontractor for other products. I would still like to show the material on the BOM and possibly be able to roll up its cost into the product, whether I purchase or supplier purchases.

Any ideas?

If you want show this item as part of BOM this has to be a modification… and quit big one – especially on invoicing part. You will have to receive item as part of Subcontractor Invoice and consume at the same time…

The easy solution is to put these materials as part of the Routing for the item.