After a long search, I came up with the idea:
edit the /etc/profile and add the below loop to the end but before TRAP..
#!/bin/ksh
ROOTY=$(whoami)
if [ ${ROOTY} != root ] ; then
for i in `who am i |awk {'print $1'}`
do
RID=$i
UNIXADM=$(sudo cat /home/root/unixusers | grep -Fx $RID | wc -l)
if [ ${UNIXADM} == 1 ] ; then
cat /etc/motd.unixusers
fi
done
fi
where /home/root/unixusers will be the user list /etc/motd.unixusers is the user specific motd