Good question!
But unfortunately it doesn't work this way. Daz Studio doesn't really know the concept of project files; at most you're saving a scene which is essentially a file with a whole bunch of references pointing to assets in your library.
The good news is that it doesn't really matter where those assets reside (meaning: in which library, as long as they are in "a" library) but that's the best you'll get.
I suppose you could collect the assets manually yourself, copy the whole lot to a dedicated folder and then use that as a source to build a new Daz install package. Of course, depending on the way you set up your library this could become quite a tedious task.
Not directly related to your question but this might be useful to know... keep in mind that Daz Studio can maintain multiple libraries. For example... in my setup I have "My Daz library" in which all my saves end up, I have the "Daz 3D library" in which everything from the Daz store gets installed to, but I also have a "Local stuff" as well as "Renderotica" library which I use for 3rd party assets and "naughty" 3rd party assets ;)
The reason I mention this: Daz Studio doesn't really care where something is located, as long as it is available in "a library".
So... for the sake argument let's say my "Local stuff" library is on C, and my Renderotica stuff on D. It would be perfectly fine for me to move assets from my local library to the Renderotica library; all my current scene files will continue to work without a problem.
Maybe food for thought?
Hope this could be useful for you!