1. Create a New Operator
SQL Server Agent -> Operators -> right-click -> New Operator
2. Choose a Name (e.g. "Group") and enter multiple emails in the E-mail name: field, separated by ;
a@gmail.com; b@gmail.com
3. In your SQL Job Notification, select "Group" as Operator and that's it
Source
http://www.dbanation.com/?p=416
