BOM Creator Requirement

I have BOM of my machinery product, in which i have many raw materials and sub assembly.

Now there is some sub assembly not which i don’t to create as item and then create that sub assembly’s BOM, instead of doing that i want to add one group of raw material with Name or note

which help me to understand the better with BOM and don’t need to create small sub assembly

can this possible in current BOM Creator, i tried but i don’t find any solution.