How can I show only first level terms on a dropdown taxonomy exposed filter? I have a 2 level taxonomy tree: Countries and cities. I also have a view of content, all of which are marked by first level terms (countries) of that vocabulary.

My taxonomy tree is like that:


Country 1

City 1
City 2
City 3

Country 2

City 4
City 5



In an exposed filter over the view, I want to show only the first level terms (countries) as options. Is it possible?
This question is very similar to How Can I add a Hierarchical taxonomy Select in views filters and when editing content in Drupal 7

I will say that the easiest method I can see is to add an exposed field by the name of "Content: Has taxonomy terms (with depth)" this way you can select the vocabulary(unfortunately only one) and also select the depth.