Return value
     array - 
     a nested array of anonymous objects.
    
     If $nestGroups set to FALSE, you
     can jump over the next paragraph.
    
      
     Every array entry contains an object per group.
     This object has two attributes:
     
| groupname - the name of
       the group | 
| addresses - an array of
       all addresses of a group | 
    
     The addresses array consists of an
     array of anonymous objects for each address. This object
     comes with the following attributes:
     
| personal -
       the name of the address owner | 
| comment -
       an array, an entry for each comment per address | 
| mailbox -
       the name of the mailbox, the part before the @ | 
| host -
       the name of the server, the part after the @ |