This would be huge. We frequently use sequences to follow up with contacts from trade shows, and there are often multiple people from the same company that stop by our booth together, so being able to follow up with all of them in one thread just makes sense. Sending individual emails to each person when they’re all close colleagues kind of gives away the fact that it’s at least somewhat automated and impersonal.
Shocked this isn’t possible and even more so that this thread and the feature’s status haven’t been updated in so long.