Track page view AND parent group view

i have lots of articles on my website in different categories.

I also have topic groups that are bit like “tag” groups. An article can belong to several groups (recoginzed by IDs).

Now i want to track, how many visitors have visited articles from a specific topic group.

What is the best way to achive this?
I probably have to define targets and add an event tracker… or is there another (better) way without defining targets (because i have lots of groups)?