On the other hand, if you were to connect the other clients using Connect, install AC on the Essentials machine, you would have a domain network.
FYI: With Essentials, you don't use Exchange. You basically have Exchange in the cloud. You subscribe to Microsoft Office 360, and everyone has Word, Excel, Powerpoint and Exchange. Some versions come with SharePoint that dreaded program, which remains clouded in secrecy, lol.