Mass @mention anyone assigned a task in a project

I need to communicate a message to everyone who is assigned tasks within a project. It would be great if there were a default user group for this. 

Here is my scenario: I put a project on hold a few months ago, but now it is ALMOST time to reactivate it. I would like to send a mass @mention to everyone on that project team (i.e. those are assigned tasks in that project) to let them know we've had some movement, but not enough to reactivate the project. I ended up sending an email because it was the quickest way, but email is counter-intuitive to our "if it's not documented in Wrike it didn't happen" mantra.