The straightforward way is unavailable to us. We need to work around the issue. The following is not a perfect solution and syncing events only happens every so many hours. 

If you plan to do this, you must publish the Outlook calendar you are sharing. That said, people from in-district may be able to find it and add it to their calendars and it is published to the web. While unlikely someone would stumble upon it, it is something to keep in mind. If you put sensitive information on your calendar, this is not an option. Be sure that any documents you attach have appropriate sharing rights (ie. restricted, not "Anyone with a Link"...)

In Outlook Calendar

1. Go to settings in Outlook Calendar

2. Shared Calendars

3. Publish a Calendar

4. Choose Calendar and what you details you need to see

5. Click Publish

6. Copy the ICS link

In Google Calendar

1. Scroll to "Other Calendars", click +

2. From URL

3. Paste in address

4. Add Calendar