Group libraries are a great way to work privately with others on a project as well as a great way to publicly share your research with others around the world.
You can initiate the creation of a group library by:
1) Click on Create Group under the Groups section:
2) Key in the Group name and select the type of group it will be:
Take note that for the free version of Mendeley, you can only create 1 Private group. If you want to have more private groups, you might want to think about upgrading your Mendeley to the premium version.
To invite members into your group is easy, just click on the group you want to add the person to, click on the Members tab and type in the email address of the person you want to invite into your group.
Note that for the free version of Mendeley only allows you to invite 3 members.
To delete groups, just do a right click on the group that you want to delete, and select Remove Group. Your group will be deleted.