Let public see comments but not allow them to comment.

Hello,

using commute with k2 component.
Is it possible to set unregistered users can see comments from the registered users they are not allowed to comment by them selves?

Best would be ıf the could also see the comment box but with the notification 'To comment this article pls register.'

Tnx and best regards,

Alp

It would be great if you could integrate Facebook ids to this component.