Assign module to k2 item page

How can I assign a module only to a k2 item? All my articles are k2 items and I can not control what modules are displayed on those pages. I want to display diferent comercials depending on the article. But in the editor I can not see those articles when I choose where the module will be displayed.

Hi,
you have to add article as menu item. And then in menu asigment settings choose page where it show s up or check site where it should show.

This means that I will have a lot of menu items when I click on a menu. Am I right?
In this case it will not be a good idea to do it.

You can also made some category where you will add all this articles and add category to menu. Should work.