Here is an example, we have an outlook email group (firstname.lastname@example.org) which consists of 10 people (email@example.com, firstname.lastname@example.org, ……), and we have created a server user with email address - email@example.com and subscribe to a dashboard so that all of the 10 people will receive a snapshot of the dashboard.
Now, we want to create another outlook email group (firstname.lastname@example.org) which consists of 2 people who are already in email@example.com, do we need a new server license for firstname.lastname@example.org in order to subscribe?
What sort of Server license do you have ?
If it's a named user license, then creating email1@ will violate your License Agreement.
I faced exactly the same issue with a client last month, the proper (legal) method is to buy licenses for Jack, Jim and all other "real people"