Hi Shari,
Here's one way:
Create a slide show in a slide show:
First save your first 12 slides as a seperate slide show.
Set up the show to loop continuosly until 'Esc'. SAve it
as a PPS file.
Create a second slide show with the remaining slides (13+).
On the first slide, click on insert, object, create from
file, browse and choose your PPS file, click ok. Drag the
embedded presentation off the screen.
In custom animation, check the object, click on the
multimedia tab and change Don't Play to Show. Click on
the order and timing tab and set it to start automatically.
The end result is an embedded presentation which runs
continuously until you press escape and then the rest of
the presentation runs as you specify.
A word of caution though, if you change the first
presentation, you'll need to reembed it for the changes to
show up.
I don't know if custom shows will do the escape trick,
that's why I'm telling you this method.
HTH,
Ms G