A. Outlook has an elegent solution to the problem. As long as the messages share the same Subject , gathering them together for easier viewing is a snap.
Open your Inbox and click on any of the messages in the thread. Then select View, Current View, By Conversation Topic . In the screenshot below, the three e-mails share the same Subject (Re: letter), and by clicking on the plus (+) sign on the left side of the screen, the entire thread now will be grouped under one header.