Unfortunatley there is no easy dynamic way to pull this off.
you would need to check on which page you are and then add a rule for that page manually.
an example: each page gets unqiue body classes appended. so for example the frontpage gets the class home:
now in your custom.js file at the very top search for
my_lightbox("a[rel^='prettyPhoto'], a[rel^='lightbox']");
and change it to:
var nolightbox = jQuery('.home');
if(!nolightbox.length)
{
my_lightbox("a[rel^='prettyPhoto'], a[rel^='lightbox']");
}
if you want to exclude the page with id 12 and the home page for example the nolightbox var would read:
var nolightbox = jQuery( '.home, .page-id-2 ');