If you are looking to create multiple galleries but have only one displayed at any one time, then you could do one of the following:
(1) Create each of your galleries separately using svBuilder-Pro and keep each gallery in a separate, uniquely-named, folder
(2) 'Download all embed examples' from the link on this page
(3) Extract the 'simpleviewer_embed_examples' zip file and navigate towards the 'examples/multiple_galleries/' folder
(4) Put all your gallery folders alongside the 'gallery1' and 'gallery2' folders (ensuring your own gallery folders are not called 'gallery1' and 'gallery2' at this point)
(5) Edit the 'gallery1/index.html' file in a plain text editor and link to each of your gallery's 'index.html' files in the <div id="header"> section (the existing file will give you an example as to how to do this)
(4) Replace the 'index.html' file in each of your own gallery folders with the newly modified 'index.html' file
(5) Delete the 'gallery1' and 'gallery2' sample galleries

Alternatively, you could install and use jAlbum and the SimpleViewer skin.
Once installed, you can drag and drop multiple folders into jAlbum's interface and, after clicking the 'Make album' button, the resulting album will comprise a gallery for each folder, all linked together by a JavaScript navigation tree.
The skin comes with SimpleViewer Standard but can be upgraded to SimpleViewer Pro by following the instructions here.
SimpleViewer Pro options can be entered into the 'Pro Options' text area in the skin settings 'Viewers/SimpleViewer/Pro' tab.