Version: 10.0.2.5303
Hi,
I've just found that when members of a group have access permission to create blog posts, they can access the Posts area (Manage > Manage Blog > Posts) and view ALL unpublished/draft posts of other users.
Surly users should only be seeing their own unpublished/draft blog posts, unless strict permission is given or are the Owner of the group.
Regards,
Simon