Solved ! The round robin was a shared event. When made into a team event, it was available to select to create a new integration rule with mailchimp.

Hey there @A.J.18287 - thanks for your topic! 

Check out this help center article about our MailChimp integration, to start. 

What are Mailchimp rules?

Creating rules allows you to automatically add invitee information from Calendly events to Mailchimp audiences based on certain event types. When an invitee is created after scheduling a Calendly meeting, they are added to Mailchimp as a contact.

Creating rules for Mailchimp

Steps for setting up rules:

1. Go to the Calendly integrations page and select Mailchimp.

2. Select “Create a Rule” to set up your first rule.

3. Under “When someone schedules with this event type” select the event type that you would like to use to add invitee information into Mailchimp.

4. Select the Mailchimp audience that you would like to add invitee information to.

5. Select one or more Mailchimp tags to associate with this rule (more information on tags below)

6. Click “Save” to save your changes.

Note about GDPR:

• Please ensure that your invitees grant consent to receive emails from you before you add them to a Mailchimp audience. Once your invitees opt-in, we add them to Mailchimp audiences as subscribers.

• If your invitees are in General Data Protection Regulations (GDPR) countries, we add them to Mailchimp as "transactional contacts" (who only receive messages about orders, shipments, test messages, etc.) and ask them to opt-in to future emails.

If these steps/resources do not help, please log into your Calendly account and click “help” to reach out to our support team, available 24/7, for more individualized support in resolving your issue. Thank you, and have a great day!