Hello Gary,

I'm not Hans-Peter but I think I can help.  I took a look at your site and everything seems to be working as intended.  The page that your link takes me to leads to a page with the blog modules installed and the most recent blogs entries showing.  The most recent entries are for all of the entries for all of the blogs so all of the users post will show up in it.  In the box titled Blog Entries if you click the Principals Blog the main box updates to show only your entries and the same hold true for the PTA link. 

If you don't want it to work this way you can use the RSS module and one of the example XSL files to show only the feed you want on a page.

The parent / child relationship makes more sense to me as a Title / Subject relationship where the Parent is say the main or general topic and the childeren are sub-topics of the general theme.  On my sites blog I've got a Parent called General views and under that I have General aviation, RC Aviation, and computing.  Yours would be something like The Principals blog then child blogs of say school, district, activities, CED.  That way people who see your blog and want to see everything you have to say about the school but don't care about the district can just look at what they want. 

Each user you have needs to create their own blog.  To get them to show up only on specifc pages you might need to configure them as personal blogs.  Since I've only got the one I don't have much experiance with that though but I'm sure Peter of someone will mention how to get that set up.

Have you thought about letting your students post blogs to a interal network?  I had an english teacher that made us write at least one journal entry a day.  He used them to guage our english skills but also said it was for the future.  I didn't know what he ment then but I treasure them now.  A blog is just the new way to do it.  :)