You may need to create a mechanism which exports the Users & Group information to a .csv file or an Excel file based on which you can create a WebI report.
This could help you for LDAP Export Exporting Data to Excel from LDAP Server
Based on the export from Step 1 you can create a WebI report though the values in Excel varies time to time.
Creating a Webi doc off of an unmanaged Excel data source on a network share
Thanks
Mani