Run Rule: When owner and created by are different

Run Rule: When owner and created by are different

Is it possible to create a rule to send a notification when:

Owner isn't = Current User

For example I want to send a notification when a case is created for somebody else other than the creator. The only way around this that I can see.... is to setup multiple rules for each user.  EG:

Case Owner is = X
AND   Created By isn't = X

Case Owner is = Y
AND   Created By isn't = Y

It becomes very awkward when we have lots of users.

Thanks for your help