Ok, I am not sure if my reply got posted, so posting a second time just in
case:
Here is how you can do this:
1. If you have already created the stationery pages, they will be in the My
Stationery group (or My Templates in OneNote 2007).
This is actually just a special section file that is stored in this
directory: C:\Documents and Settings\%username%\Application
Data\Microsoft\Templates
(I say "special" because for every page there is also a hidden stationery
name property that got put in there when you were prompted for stationery
name. This is the name that is used to display stationery in the pane.)
2. You can open the Templates directory as a notebook and reorganize your
stationery. To do this, click File > Open Folder (Open > Notebook in OneNote
2007). You now have the folder open with one section file in it: My
Statinery, or My Templates in 2007
3. Create other sections next to this one - e.g. Agendas, or Personal. Move
the pages from the My Stationery/Templates section to these new sections. In
ON 2007, you can just drag and drop.
Don't forget to remove the empty pages from the Agendas and Personal sections.
4. Now, close the folder (notebook in 2007) by right clicking it and
choosing "Close"
5. Restart OneNote and go to the stationery pane. You should see your neew
groups in the pane.