hello,
 
Is it possible to setup up a filter match based on variables for date?  example thinking...
 
filter f_date { match($YEAR-$MONTH-$DAY.*); };
 
#log the files
log { source (s_udp); filter(f_date); destination(messages); };
# set it up
destination hosts {
        file("/syslog/NT-SYSLOG/HOSTS/$HOST/$MONTH-$DAY-$YEAR"
                owner(root) group(root) perm(0644) dir_perm(0755) create_dirs(yes)
        );
};