As the question states, is it possible to have to have more than one Exchange service serving the same domain for a single store? Is clustering required or is like Active Directory (just promote and add to the domain). This question has server standard in mind (not enterprise or data center where clustering is possible). If this is possible, what steps should I take to make this happen? The benefit I am looking for is replication and fualt tollerance (take one of the two servers down, but still have service available).
The answer is yes. For more details, you'll need to specify which version of Exchange you've got.