Photo gallery with several subjects

I’ve applied the xml photo-gallery tutorial but would like to use a menu with different subjects.

With every click in a different subject I’d like to load different pictures into my gallery. I’d like to use one XML sheet with different nodes for the several subjects.

I’ve seen the tutorial on XML based drop-down menus but I have no clue how to implement and link this into my photo gallery.

Who can give me advice?

Noucky, a novice!