Sorry, i'm little bit confused!
A User can create "Series" in the backend (overview.php)
I would to use the "Series" in a subsite (product.php) of overview.php.
+ Overview (create Series)
--- Product (use Series)
now it is for me of the canned -> backend.
I have wrote a class (Data Object) where users can create "series".
Now I would like the corresponding lower within the backend that the user can draw on the extensive series and can select a drop down and store.