There used to be one in Sao Paulo, but I think the organizer stopped paying for the meetup.com subscription. There's still a meetup page for one in Pelotas (https://www.meetup.com/Pelotas-Emacs-Meetup/) which is inactive, but maybe it can be turned into an online meetup? EmacsATX uses Google Meet; I can also set you up on BigBlueButton if you prefer something that uses free/libre software.
Here's how I would approach it:
#+STARTUP: noptag #+TAGS: #+TAGS: [ GT1 : tagA tagC tagD ] #+TAGS: [ GT2 : tagB tagE ] #+TAGS: [ GT3 : tagB tagC tagD ] #+NAME: source | tag | Q1 | Q2 | |------+----+----| | tagA | 9 | | | tagB | 4 | 2 | | tagC | 1 | 4 | | tagD | | 5 | | tagE | | 6 | #+begin_src emacs-lisp (defun my-sum-tag-groups (source) (cons (car source) (mapcar (lambda (tag-group) (let ((tags (org--tags-expand-group (list (car tag-group)) org-tag-groups-alist nil))) (cons (car tag-group) (seq-map-indexed (lambda (colname i) (apply '+ (mapcar (lambda (tag) (let ((val (or (elt (assoc-default tag source) i) "0"))) (if (stringp val) (string-to-number val) (or val 0)))) tags))) (cdr (car source)))))) org-tag-groups-alist)) #+end_src #+begin_src emacs-lisp :var source=source :colnames no :results table (my-sum-tag-groups source) #+end_src #+RESULTS: :results: | tag | Q1 | Q2 | | GT1 | 10 | 9 | | GT2 | 4 | 8 | | GT3 | 5 | 11 | :end: