I have an Email Service, to handled incoming emails, which is replacing Email-To-Case, to handle duplicate cases (by matching the Subject of the incoming email with existing cases). This is working fine.
Trying to come up with a solution, I was able to find the following article (https://customers.internetcreations.com/KnowledgeDetail?name=Include-Additional-Email-Addresses-on-Auto-Response-feature-does-not-work-with-Email-to-Case-Premium), by 'Email to case premium' which is utilizing Case Teams as part of an independent workflow rule bonded with the appropriate email alert.
Is there any way to achieve this without Case Teams? My Case object does have a custom 'Additional CC' (and 'Additional BCC') custom fields, which holds the email addresses of the recipients, but I am not seeing any option to add custom fields in the Email Alert: