Bringing a whole team into a group no longer means adding people one by one. Every group's Edit page now has an Invite by Email button: paste a list of email addresses (one per line, comma-separated, or straight from your mail client as Name <email>), pick the role they should get, and hit Invite.

People who already have an account become members right away. Everyone else receives an invitation email and is added to the group — with the chosen role — automatically the moment they register. Duplicates are folded, anything that isn't an email address is skipped and reported, and re-running the same list is always safe.