Ordinarily ONE iPhoto Library suffices, because it can contain any number of "albums"
However, what you need/want is iPhoto Buddy v 1.3.4;
an application specifically designed for managing multiple iPhoto libraries.
Go to: http://www.iphotobuddy.com/
It is a perfectly composed Web Page. An exemplar for web page design — I M H O that is.
Go on. Take a look. I'll wait. "iPhoto Buddy allows you to use more than one Photo Library with Apple's iPhoto, and makes it easy to switch between them. But first, each Library must be added to Buddy's Library List.
Your existing iPhoto Library (the Default Library) has been added to the Library List for you. You can add additional existing Libraries, if you have them. You can also create new (empty) Libraries and add them to the Library List.
To add an existing Library, simply drag it from the Finder and drop it on the Library List.
To create a new Library, choose File --> Create A New Library.... From the standard 'Save As' Dialog that appears, enter a name and location for your new Library, then click the 'Create' button. iPhoto will launch and open your new, empty Library into which you can begin importing your photos.
To view and edit one of your Libraries with iPhoto, simply select it from the Library List and click the Launch Button. iPhoto will launch and open the selected Library.
See the iPhoto Buddy Manual for more details."