I don’t know anyone in Canada that isn’t a new Canadian that uses anything other than the default sms app on their phone. (FBM and Insta and what not don’t count in my example).
I don't know about the underlying technology, but every client I've used for the past couple decades supported groups.
However, they absolutely sucked. There was no way to leave. Unless someone made a new group without you and everyone used that, you'd keep getting messages.