title: How to automatically trigger a change in TODO state in Emacs org-mode
body: <p>Using Emacs org-mode, I often have a list of TODO items that I want to have active one at a time, in sequence. For example when the Item A in a list is marked "DONE", then I want Item B to be automatically be marked "TODO". How do I make this happen? This should not be any kind of general behavior, it should only happen with specific pairs or lists of items that I chose. </p>