Description
bool 
chgrp ( string filename, mixed group )
     Attempts to change the group of the file filename
     to group (specified by name or number). Only the
     superuser may change the group of a file arbitrarily; other users may
     change the group of a file to any group of which that user is a member.
    
     Returns TRUE on success or FALSE on failure.
    
Note: This function will not work on 
remote files as the file to
be examined must be accessible via the servers filesystem.
Note: When safe mode is enabled, PHP checks whether 
the files or directories you are about to operate on have the same UID (owner) as the 
script that is being executed.
     See also chown() and
     chmod().