Use an affiliate audience filter to include attendees attributed to a particular event affiliate, or exclude that affiliate's referrals.
Add the affiliate filter
Go to Email & SMS > Emails and open Campaigns.
Edit the manual or automated email, then open Audience.
Set Audience type to Attendee.
Select Add filter. In the field chooser, select Marketing Source > Affiliate.
Choose Equal To to include that affiliate's referrals, or Not Equal To to exclude them.
Choose the affiliate from the event's affiliate list.
The screenshot shows an unfinished Affiliate rule. Choose a value to complete it. The existing Ticket rule is an example of another condition that can also restrict the audience.
Saving and availability
Complete audience rules save automatically as you choose their values. Check the matching-recipient total and all existing rules and groups before sending. A new rule does not remove other audience conditions. Use Save or Save and Close to save other changes to the email.
Audience rules cannot be changed for transactional emails, follow-up emails or a Broadcast email that has already been sent. Editing also depends on your event access, plan and trial status. An unavailable feature may show an upgrade or access restriction.