Handling shared content without multisite?
You could have a look at the Feeds module. You should set up one site as master (where news and events are entered) and use the Views module to publish an RSS feed of the content you want to share. Now on the other sites, you install the Feeds module and configure it to pull in the RSS feed and import the content from the master site.

Downsides to this approach:


There will be a delay between the publishing on the master site and the import on the other sites.
This especially works well when all content is entered on site. If you need content to be entered on all sites, things quickly get more complex.
Once the content is distributed from the master site to the other sites, it can be edited on all sites, but the changes will not be synchronized across all sites.