Notifications: adjust trigger time/activation for sending mails

Hi everyone

Is there any way to adjust ‘WHEN’ notifications about modified folders/files (etc.) will be sent?

and to be more specific, it could be a problem for several mail-servers when the following procedure ocures:

  1. activate user (without adding his e-mail address, is member of an existing group & group-share)
  2. user is using nextcloud excessively
  3. administrator or user adds his/her e-mail
  4. e-mail flooding happens from the beginning of user-existance

Anyone has an idea how to set (or add) the trigger to send e-mails only for newly added/modified files/folders AFTER mail-address has been set?