So this popped up on [1]Reddit:

     Extensible Dependencies 'N' Actions (EDNA) for Org Mode tasks

     Edna provides an extensible means of specifying conditions which
     must be fulfilled before a task can be completed and actions to take
     once it is.

     Org Edna runs when either the BLOCKER or TRIGGER properties are set
     on a heading, and when it is changing from a TODO state to a DONE
     state.

     For brevity, we use TODO state to indicate any state in
     org-not-done-keywords, and DONE state to indicate any state in
     org-done-keywords.

   (from nongnu.org: [2]http://www.nongnu.org/org-edna-el/)

   I don't have time to dig into this right now but this looks
   particularly interesting.
     __________________________________________________________________

   My original entry is here: [3]org-edna: Extensible Dependencies 'N'
   Actions (EDNA) for Org Mode tasks. It posted Wed, 20 Dec 2017 07:05:51
   +0000.
   Filed under: emacs,

References

   1. https://www.reddit.com/r/emacs/comments/7kyfgn/org_edna_adding_extensible_dependencies_and/
   2. http://www.nongnu.org/org-edna-el/
   3. https://www.prjorgensen.com/?p=768