1. In the event dashboard, click on "Promotions" from the side bar.
2. Click on "Promotion Mailers" under "Content"
3. Click "Edit" to scope it to a group of people.
4. Click the dropdown under "Send To" and select "Contact Tags" option
5. Click the dropdown under "Select Contact Tags"
6. Select the desired Tag. This can also be scoped to more than one group by selecting multiple multiple groups from this dropdown.
7. Click on "Save" to persist the changes
8. Your mailer will be scoped and placed in the draft section.