How to set the blog home page

On my site I am using posts to publish “updates”. I have a template for this called “template_updates_index.php. This file goes through the loop and gets all the update posts. So this is basically is my blog page.

This works good, except my main navigation gets messed up(does not show the on state anymore, I use the wp menus) when I go to one of my single updates or any archive page.

How would I do this? I would like the main nav to still show the on state for updates, any time I am on any of the updates(blog single pages).

Thanks a lot for any help with this!!!