Create a Distribution Group
You can create distribution groups to assign work items or send notifications to a group of contacts instead of an individual contact.
When a contact is added to a distribution group associated with a project, the contact starts receiving project notifications and automatically has access to the work items associated with the group.
When a distribution group is assigned to a work item, any member of that group can take action on the work item to change the ball-in-court for that work item.