Hi Janet,
What I can propose, is the TA SE16 (Data Browser).
- SE16 -> Table STPO -> Menu Bar: Settings/Fields for Selection -> 'IDNRK'
- put your material (or even a whole list) in the field 'IDNRK' and execute -> you'll find all the BOMs where this given material is used.
If you would like to match the BOM numbers to the header material, you can do in the TB MAST (Material-BOM assignment)
However, if you change your layout in CS15 (and select also the field 'Bill of Material'), you should see to which BOM number(s) the entered material is assigned to.
BR,
Dora