Hello uber programmers!

I like to display a specific image on a page based on "its top-level root tabid". 

Play (Root page - tabid=23)
-- Slide
-- Swing
-- Pool
Yummy (root page - tabid=34)
-- How to Eat
-- How to swallow
-- Things you can't eat

I would like to display a "Kids" image on all pages under "Play" including Play, slide, swing, and pool page. I also would like to display a "Fruits" image under "Yummy" including Yummy, how to eat, how to swallow, and things you can't eat page.

I read the manual, googled it, of course searched this forum.... no luck so far. I am guessting it's something to do with "IntStartTabID" but i am not sure. Once I find a way to identify the "Root TabID", i can just send the variable to an external javascript code and replace the image on the page. (if tabid=32 then replace the image on the page with that image....,,, if tabid=43 then use this image...).  it's not dynamic solution but  the number of top level items are only 5 or 6......I was also thinking to create 6 skins for all root menus and do "Copy design to descendants" in admin setting. But... it's not my favorite solution.....Hmmmmmmm I am stuck.

ANYWAY, do you know any way to make it work without putting a little javascript on every single page to specify the image? or, do you know any modules does the similar job I want? or even a hint?

Thank you!