Groups are a simple way for you to collaborate with your colleagues and share a collection of documents. Any member of a group may upload documents to it.
You can create 1 private group with a maximum of 3 users per group. Paid options allow you to increase these limits. You can create a group by clicking on "Create Group" in the left hand pane.
Mendeley's Groups feature is available via both Mendeley Desktop and the Mendeley Online Reference Manager.
There are three types of groups:
Share documents and citations with others by inviting them to participate in the group. With the basic Mendeley plan we may have only 5 private groups of no more than 25 members and limited (100 MB) storage space for group resources. These private groups are visible only to members, who can share papers and notes.
Public groups that are invite-only
These publicly visible groups have a restricted membership list, which is controlled by the group's owners. You can upload PDFs, but they will only be available to others if they have access through their own institutions (or if they are Open Access articles).
Public groups that are open
These are publicly visible and everyone can contribute citations.