Combining 2 files possible?

I have 2 files, and I want to keep them seperate.

1 = the main item (dress) with some materials
2 = Expansion file with more materials for the dress.

Now I have 2 icons showing up in Daz in the smart content.
is it possible when i click on the main item, that the expansion contents is showing also under the materials for the main item?
or do I really need to combine the 2 ZIps in 1 and then process them.

Will to be honest I really don't know I have never tried something like that.
This is just off of the top of my head I'd say combined them make the smart
content make the DIM close CDDS. Open the zip copy the support folder to
the original main folder now open CDDS load the original main folder do not
check add smart content lines click create manifest. Now do the same with
your expansion content except don't add the support folder just create manifest.