Extension:GroupsSidebar

The GroupsSidebar extension allows to add sidebar elements for specific user groups. If you have usergroups and would like to add sidebar elements just for certain usergroups, you can use this extension.

System messages
The resulting message names are "MediaWiki:Sidebar-groupname" whereas groupname is something like "sysop" or "user". For example, the message name could be "MediaWiki:Sidebar-sysop". You can edit it the same way you edit the normal sidebar.