How to have variable headers on different pages of a chapter?

Hello,

(Running FrameMaker 8 on Windows XP.) I'm trying to figure out how to set up a system variable to use to construct a running header in the Master pages of a chapter. I would like the chapter to have more than just two header variants (one for left-hand pages and one for the right). I want the header to reflect conditions that are local to the page being displayed.

First, here is the basic structure of the chapter:

Chapter Heading

   Heading 1

      Heading 2

            blah blah

      Heading 2

            blah blah

      Heading 2

            blah blah

    ...

  Heading 1

        Introductory text (several pages of body text and lower-level headers)...

      Heading 2

etc

On any given page, I want the running header to display the text of the most recent Heading 2 title to be used. However, if a new Heading 1 title was used more recently than the most recent Heading 2, and there is no text of type Heading 2 on that page, then I want the running header to display the text of the most recent Heading 1 title.

For example, suppose the "introductory text" in the above outline were to take up a few pages. On one of the pages having only body text, I would want the running header to display the text of the Heading 1 just above it, rather than the text of the Heading 2 title preceding that. In other words, I would like some sort of decision process, on a page-by-page basis, on which title's text it should use.

Is it possible to do this in FrameMaker 8? I tried using the <$condtag> building block, but I couldn't even get it to display anything meaningful, much less the correct text. I think I was misusing this building block - that it's only for use on pages that have conditional text, is that correct? My document has no conditional text in it at all.

Can anyone suggest how I might accomplish what I'm trying to do?

Thank you!

Joyce