Hi Jason,
If you use panel context, the phonebook will inherit them. In fop2.cfg you have to create the contexts like:
[departmentA]
user=100all
buttonfile=depta.cfg
[departmentB]
user=200all
buttonfile=deptb.cfg
And load the panel like:
http://x.x.x.x/fop2/?context=departmentA
Whend doing so, each context will have its own phonebook. If departments share the button and user configuration, just use the same for both, but you must log with the correct context in the url.