How I would approach this issue is I would first find a comment notification plugin that works well and has been recently updated. This one seems to fit the bill just fine:
http://wordpress.org/extend/plugins/subscribe-to-comments/installation/
Then I would come up with some way of marking the pages that I want comment notifications on. You could do this with a custom metabox (http://wp.smashingmagazine.com/2011/10/04/create-custom-post-meta-boxes-wordpress/) or even with a category or specific tag.
Finally you need a way to allow the comment subscription to only work on pages that meet your criteria. The plugin I linked above gave this wonderful hint:
Optional: if your WordPress theme doesn’t have the comment_form hook, or if you would like >to manually determine where in your comments form the subscribe checkbox appears, enter >this where you would like it:
So, it would be pretty trivial to figure out the function that shows the checkbox or (even better) by examining the plugin – to figure out what filters and actions it uses, and simply remove them using remove_action() and remove_filter() – for any post that doesn’t meet the subscription criteria.
I would probably use a filter for ‘after_setup_theme’ since that fires after ‘plugins_loaded’.