The only way I can see to do it with #+ARCHIVE lines would be to have
my teaching.org look like
* Heading setting ARCHIVE line for following tree
* Intro to Logic Fall20072008
* Heading setting ARCHIVE line for following tree
* Intro to Philosophy 20072008
etc.
That makes for ugly clutter, IMHO. (The problem is acute in my
intended case, as each level 1 heading needs its own ARCHIVE line.)
I would say that this only requires a litte creative restructuring,
and to give up the idea that in teaching.org, courses must be level 1.
In teaching.org:
* Intro to Logic
#+ARCHIVE: archive settings for logic
** Fall200072008
* Intro to Philosophy
#+ARCHIVE: settings for philosophy
** FALL20072008