Currently we have a project with no Notification Scheme applied. So no notifications are distributed.
Now we would like to send notification only to users tagged in description/comments. How to achieve this?
When setting up a Notification Scheme there is a need of selecting of a user definition (Assignee, Reporter, Group...) but there is no chance to save it without anything selected so only Tagged users would be notified.

Any idea how to approach this case?