There are other groups within Microsoft, but they usually follow a presentation format rather than a collaborative discussion. Off the top of my head, Phil Bernstein[1] and Hanuma Kodavalla[2] run great database seminars for invited speakers. I regularly attend and have presented in both forums; Phil's crowd is mostly researchers, while Hanuma's is mostly full of SQL engineers. Different from a small reading group, but still great.

Appreciate the paper link! We like going back to the basics sometimes, so I'll definitely take a look.

[1] https://en.wikipedia.org/wiki/Phil_Bernstein

[2] https://scholar.google.com/citations?user=9eNQbZUAAAAJ&hl=en