How to use hierarchy with taxonomy queue?

I've created a two level hierarchical 'News' vocabulary, like this:

Main category 1
- subcategory 1
- subcategory 2
- subcategory 3

Main category 2
- subcategory 4
- subcategory 5
- subcategory 6

etc.

Main categories are 'containers', there are articles just in the subcategories.

I've created a taxonomy queue related to this vocabulary. When I submit a new article, it is easy to add it to the queue of the subcategory. But it should added in the same time to the main category of the subcategory too (manually or automatycally).

From an other view: in the queue of the main category it should be possible to choose articles from any of the subcategories (it would be selection from a list like taxonomy/term/1/all).

But it is not clear to me how to do it. (Maybe I should create my vocabulary another way...)

Could you help? Thanks!