I would suggest continuing this discussion in the calibre forum's
Library Management subforum.
What I suspect you need to do is to create a directory called whatever you might want (I used Libraries) and subdirectories under it for your existing and to be created libraries. Move your existing calibre library (right click on the library icon, then Switch/create library. Browse to the new subdirectory for your library, select Move the current library to new location and click OK. Repeat this for the new libraries you want to create but select Create an empty library at the new location and check Copy structure from current library.
Hope this is of some help to you.