Thank you for this suggestion. However this can bring two big problems.

1. The mentioned group may have thousands of users and email server may be overloaded or stop sending after X email. All hosting services has email sending limits per hour and day.

2. This is a great tool for spammers. They will register as a regular user and send emails to all users using 4 - 5 group names with @ prefix. This feature may be a big gap in wpForo antispam system.

Is it, or will it be possible to setup @ mention groups that have specific users listed?

So:
@group1 would notify member1, member2, member3

@group2 would notify member1, member4, member6 etc

It's a bit of an effort to type out all the names if we need to notify multiple users.

I was thinking about setting up a user for the group, and having that user have multiple email addresses as a workaround, but it doesn't look like wordpress supports multiple emails per user.

Thanks for any info.