Cross correlation of DNS requests for service clustering

I was wondering whether pihole could introduce a way to cluster DNS requests into services based on some engineering features such as the public suffix list from Mozilla, timestamps ecc.
Ideally if domainA request always comes before domainB request chances are that they are from the same application and if one is fbcdn.net then both are part of Facebook application.
What I'm struggling to solve is that when I analyze traffic it is difficult for me to understand whether certain requests are correlated or not