Redirect subcategory to category

[vernb]

Sorry ... I just posted this in the wrong place. Hope this is the right one!

I'm using version 1.3.9b and need to know how to redirect a subcategory to a category.

I am building a site to sell astronomical images that have been digitally remastered.


Sidebox Categories
Universe
Galaxies
Nebula
Stars
Exotics
Solar System
Subcategories:
Sun
Mercury
Venus
Earth
Mars
Etc
Earth
Technology
History

As you can see above, the Solar System Category has many subcategories. However, I need the Solar System>Earth to go directly to the Sidebox Earth category. I've searched high and low for a solution and think it may mean having to write some extra php in the template_default/sideboxes/tpl_categories.php file. I tried a couple of things but nothing worked.

I'd be very grateful for any ideas?
Thanks
Vern

[vernb]

I think I need to clarify my first post as missing indents made it hard to read.

In a nutshell, I need to redirect a subcategory to a category.

I have a sidebox menu item called Solar System within which is a subcategory called Earth.

I need this subcategory i.e. Solar System>Earth to go to the sidebox menu Category Earth.

Can anyone help me do this please?

Many thanks
Vern