As long as the widget is set to show in the what’s on section on the main site, blog items will show in the events pages where the location of the event matches the location site set in the news. If there is a specific blog posts for a specific news item then it is better to use the related items dropdown in the event page itself.
In brief, the actions are:
- Set the widgets to show where you want them
- Tag the news, blogs and projects up with the sites you want them to show on.