Just found the answer with ADD REFERRAL EXCLUSION here:
1. Sign into your Analytics account.
2. Click Admin in the menu bar at the top of any page.
3. In the ACCOUNT column, use the drop-down to select the Analytics account that contains the property you want to work with.
4. In the PROPERTY column, use the drop-down to select a property.
5. Click Tracking Info.
6. Click Referral Exclusion List.
7. To add a domain, click +ADD REFERRAL EXCLUSION.
8. Enter the Domain name. (you don't need to add the subdomains separately).
9. Click Create to save.