Each e-mail queue can have one rule group associated with it. You can create a queue rule group when you create a queue in Content Administration.
To create a rule group for an e-mail queue:
In the content browser, click the E-mail Queues item under the department you want to create a rule group for.
Find the e-mail queue for which you want to create a rule group.
Click the New Rule Group link for that queue.
Learn about rules and rule groups.
Are there any tips on using rules?