Thank you for your response.
I finally got it to work by editing the includes/helper-main-menu.php file. I added the following code
$category=get_the_category($_GET['p']);
if((int)$category[0]->cat_ID == 5) $args['walker']->__set('blog_id','40');
above the
wp_nav_menu($args);
around line 133.
That is the parent page you are looking at but it is the single page that is having the problem (by clicking on one of the links). Here is the link that goes with the previous screenshot:
Thanks Elliott. The shortcodes filter is brilliant.
For the other problem:
1. Clicking on an item on this page: http://coalitionfemmes.ab.ca/dev/?page_id=40
2. Brings you to this page:
But as you can see in the screenshot (highlighted) it shows the page as being NOUVELLES but it should be ACTIVITÉS.
Not sure why it does this. I used a filter to change the page title as it was NOUVELLES before as well.