Add a toggle to select whether you want a slideshow to continue in a loop, go to the next selected slideshow. or end until the user selects another manually.
The Project Settings window | General tab contains the "Repeat" and "Close after finish" options. The Album feature (the Tools | Album menu) allows you to combine several slide shows and play them from a menu. The Album Settings window has the "Show Play All button" check-box. This button allows you to run all the album shows one by one.