AutoCAD Inventor :: Break Association To BOM?

I'm using Inventor Pro 2011 and I'm trying to break the association of a BOM from it's assembly.  My company uses a "next assembly list" on each drawing to show the quantities and information that appear on the BOM in the next level assembly.  To achieve this we insert a parts list referencing the next level, then we turn off the visiblity of all the parts except the item we want shown.  The problem we've found with this is that we're using some large assemblies and Inventor slows down when it has to reference the large assembly on each drawing.  All we really want to show is the single line.  If we break the link to the large assembly, we feel that it will speed up the process considerably.