I think the list of invited users should reflect only those who have yet to join the group. That way we can click the resend link of each person who has not accepted the invitation, without having to check for each person whether they have accepted already. We should also be able to manually remove people from the "invited" list, perhaps, and it would be nice to have a button to automatically resend the invitations to all who have not accepted yet, perhaps with an additional message of explanation.