cat /etc/group | nawk '
{
   TUP  = split($0, field, ":");
   USERS = split(field[4],user, ",");
   if (USERS == 0) printf "%s\t%s\t%s\n", field[1], field[3], "NULL";
   for (i = 1; i <= USERS; i++)
       printf "%s\t%s\t%s\n", field[1], field[3], user[i];
}
'

lp:!:11:root,lp,printq

lp ! 11 root,lp,printq

bash-3.00$ D='lp:!:11:root,lp,printq'
bash-3.00$ echo $D |sed 's/:/ /g'
lp ! 11 root,lp,printq
bash-3.00$ echo $D |sed 's/:/ /g'|awk '{print $1}'
lp
bash-3.00$ echo $D |sed 's/:/ /g'|awk '{print $2}'
!
bash-3.00$ echo $D |sed 's/:/ /g'|awk '{print $3}'
11
bash-3.00$ echo $D |sed 's/:/ /g'|awk '{print $4}'
root,lp,printq

abhi:!:34971:3418:abhi k, Sys Admin Level 3:/home/users/abhi:/bin/ksh

bash-3.00$ echo $D|sed 's/:/ /g'|awk '{print $5 $6 $7 $8 $9 $10}'

abhik,SysAdminLevel3

bash-3.00$ echo $D|sed 's/:/ /g'|awk -F' ' '{$1=$2=$3=$4="";sub("^    ","");print}'
abhi k, Sys Admin Level 3 /home/users/abhi/ /bin/ksh

bash-3.00$ echo $D|sed 's/:/ /g'|awk -F' ' '{$1=$2=$3=$4="";sub("^    ","");print}'|cut -d "/" -f1
abhi k, Sys Admin Level 3