I don't think it's possible yet. Unfortunately, I look in all system tables and command and didn't found this kind of things.
But with a Python notebook, like what did the AI, you can reconstruct it:
first you list all the users with
SHOW USERS
then you loop for all users to get its groups with:
SHOW GROUPS WITH USER `{user.name}`
And you can reconstruct the list of users in each groups like that, and put it in a delta table with a create table.
With this table you can easily list all users in a specific group in a SQL request. You "just" need to run your python notebook regularly to update your user-group table.
Due to the special type of command that this is, you can't (to my knowledge) do that kind of thing directly in SQL, (can't "SELECT * FROM SHOW ..." for example), and there is no specific command for that, so it's a little laborious, especially if you have a lot of users and groups.