RSS feed: How to exclude some pages / $query->set syntax

Hello.

I use the “RSS Includes Pages” plugin to include my pages (I have no post at all) in my RSS feed. However all pages are included and I would like to exclude some of them.

I have seen that it is possible to exclude some posts by category, using for example the following code :

function myFilter($query) {
    if ($query->is_feed) {
        $query->set('cat','-5'); //Don't forget to change the category ID =^o^=
    }
return $query;
}
add_filter('pre_get_posts','myFilter');

But pages do not have categories. So two questions:
1. Is there any way to exclude some of them, by page id for example?
2. Regarding the filter syntax, is there any “$query->set” where I could set page ids to exclude instead of category ids? With which syntax?

Thank you in advance,
Gilbert