We have an existing DAG with 2 mailbox servers, a CAS server and a DC. Users access email remotely by going to https://xyzcompany.com/owa. Now they want to add another subdomain that will be separate from Exchange OWA login https://xyzcompany.com/owa and have different, separate email users in it that would access Exchange OWA login as https://abc.xyzcompany.com/owa. I have been searching for a step by step article to do this but can't find one.

Ok, but how do I go about creating another domain for sub.example.com with it's own email addresses reachable by OWA in Exchange when example.com already exists?roxymuzick@hotmail.com