I am not sure how it will work. If you have two SBoM from different components , each will have their own headers ( Document Creation section in SPDX specification) , I am not sure if SPDX specification gives options to keep headers for two components ?
@spatil00 I was thinking you could create a new SPDX document with it's own document creation section but include relationships from the new documents to the old documents. You could create External Document References for the 2 original docs. A relationship type DESCENDANT_OF and/or AMENDS could be used to describe the new SPDX document is derived from the 2 original documents. A relationship type of COPY_OF could be used to refer back to the original package/file/snippets from the original package if you want to make the entire operation traceable.