So I have encounter a little of the problem with generate an income have to structure a specific site using WordPress. Go ahead and take following group of URL's for instance:

The problem I am encountering is the fact that wordpress won't let me duplicate the sub groups downloads, faq and release-notes.

It is possible to wordpress plugin available anybody understands that will permit duplicate category slugs as lengthy because the category is designated to some parent?

I do not think you want to get this done. To begin with, it appears much like your permalink structure is to establish using %category%/%postname% - which by itself isn't a positive thing. Not too bad on more compact sites, however the bigger your internet site is, the greater unnecessary strain you are wearing the server. (see "Category in Permalinks Considered Dangerous" http://ottopress.com/2010/category-in-permalinks-considered-harmful/) To create multiple slugs would exacerbate the issue, I'd think.

A means around it might often be to produce a group of Pages for the sections (i.e. "Product Title 1", "Product Title 2", etc.) and also have groups setup which are known as "Release notes", "FAQ", etc. and tag you using the product title. You'll be able to operate a query within the template file to drag within the posts which are labeled using the product page title you are presently on. Then you'd possess the permalink setup you would like.