To filter content in the Discussion stream to show articles and threads involving users that you ‘follow’, you can use the Favourites functionality. From the navigation bar, click Discuss -> On my Favourites, which will give you a personalised list of Content.
You will need to to be ‘following’ the Authors in question. We don't currently allow ‘blocking’ of Authors.
If you click Edit at the top of that page, you will be able to Manage your Favourites.