Get parent category posts

Hello,

I hope somebody can answer this.
I have a main Category “Product Reviews” several Sub Category underneath such as “Filters” and “Tires” and underneath it I have Sub Sub Categories such as “Winter Tires” and “Summer Tires”. Here is a little drawing:

– Product Reviews
+ Filters
+Tires ++ Winter Tires ++ Summer Tires

Basically what I would like to do is show in Category “Product Reviews” all reviews. In “Tires” all reviews for Tires (Including winter, summer etc,) and in Winter Tires all the Winter Tires. In short, I would like to show the posts of the Category I’m in including it’s children.

Thank you in advance.