You can only communicate with people that are in your 
       group. 
       In the Community dialog box, you only see the content of 
       your current group. You don't see the content of any of the other groups. 
       (This is logical, since you can only communicate with people in your 
       group.) 
       Before examining group content, it is recommended to do a 
       Refresh of your Community dialog box by right-clicking the Community 
       root and selecting Refresh from the contextual menu (since 
       when a person changes group, his / her  Community db is 
       automatically refreshed, but the other people who are impacted by the 
       change will not have their Community dialog boxes automatically 
       refreshed).