EDIT: I found the solution. Use the 'Option' field in the collection settings.
Is there a way to add a category field to a collection so that I can use these categories to filter a dynamic list? Lets say I have blog posts in 3 different categories: Travel, Photo and Adventure. But in a particular dynamic list on the site I only want blog posts in the 'Travel' category to show.
I cant find any filtering options like this in the system or in any of the tutorials... Anybody knows?