Exclude Categories in WordPress

Hi,

Can someone help me with this issue? I have a page divided into three WordPress blogs. In one of the pages I want to show only one category (workshops), on another page other single category (activities), and finally on another page (general news).

I created two pages with each category, so far all right.

What I want to do is the possibility user can choose when he wants to post an entry of workshops or activities in general news page, if he wants to show up or not in the main news page.

I have tried to exclude the categories of workshops and activities in the news page (with advanced category excluder plugin), but if I exclude them, it doesn’t show the entries that I am interested to publish of these categories, although I use the label with two or more categories: workshops + news + school …

Does anyone know how I can decide whether to publish or not a category in the main news page?

Thank you very much in advance,

Laura