Redmine

Hello,
we encountered problem with email notifications. After checking the log files I found that notifications emails are sent from redmine in one step to smtp server. When any of the emails addresses is refused then nobody receives email notification.
I think this is wrong way how to sent emails, it would be better to sent email per user. This way only users with bad email configuration would not receive notification emails. What you think of that ? Is there any workaround for this ?
Regards,
Kamil

Environment:
Redmine version 3.4.4.stable
Ruby version 2.0.0-p648 (2015-12-16) [x86_64-linux]
Rails version 4.2.8
Environment production
Database adapter PostgreSQL
SCM:
Filesystem
Redmine plugins:
redmine_base_deface 0.0.1
redmine_checklists 3.1.10
redmine_helpdesk 0.0.15
redmine_tags 3.2.1