You can put a menu at the top of the HTML archive and Top-40 pages. The format of the file must be OPML. If you enable the feature, enter the URL of the OPML file and the name of the sub-outline that contains your menu.
There's a new prefs page that allows you to set that up. Use the same approach you use in the worldoutline for setting up an outline with multiple menus in it.
See the feature added to worldoutline on May 1.
This is what the new prefs page looks like.