The paperclip next to a group name means that this group is already connected and syncing. Let's look at a full example.
The above image shows my CCB - MC sync pairs. As we will see, all the groups in the second column (turquoise box in image above) have a paperclip next to their names. This shows that they are already connected and syncing.
Note that in this last image, two of the group names have paperclips. That is because both of them are being synced with Main Campus.