Bash Script help adduser script

[ssdude]

The script works fine,
Could I have some assistance in implementing the following:
1> Whenever the script adds an admin user: ( -a)
a directory should be created /home/admin/newuser
if the admin directory already exists then its ok, I need it to add the newuser in the admin directory not in the home directory( as it does now )

2> Whenever the script adds a normal user ( -n)
a directory should be created /home/user/newuser
if the user directory already exists then its ok, I need it to add the newuser in the user directory
not in the home directory( as it does now)

thank you

 #!/bin/bash
ADMINDIR=/home/admin
ADMINGROUP=admin
BASEDIR=/home
USRSHELL=/bin/bash
 
USERNAME=""
NORMAL=""
ADMIN=""
ARGS=""
TRUE=0
FASLE=1
 
usage(){
    echo "Usage: $0 {-a|-n} [ -c GECOS ] {-u username}"
    echo ""
    echo " -a          : Create an admin account"
    echo " -n          : Create a normal account"
    echo " -c GECOS    : Set the GECOS field for the new user account"
    echo " -u username : Set the LOGIN name"
    echo ""
    exit 1 
}
 
 
isUserExits(){
    grep $1 /etc/passwd > /dev/null
    [ $? -eq 0 ] && return $TRUE || return $FALSE
}
 
createNewUser(){
    /usr/sbin/useradd "$@"
}
 
while getopts anc:u: option
do
        case "${option}"
        in
                a) ADMIN="TRUE";;
                n) NORMAL="TRUE";;
                c) GECOS=${OPTARG};;
                u) USERNAME=${OPTARG};;
                \?) usage
                    exit 1;;
        esac
done
 
[ "$USERNAME" == "" ] && usage
[ "$USERNAME" != "" -a "$ADMIN" == ""  -a "$NORMAL" == ""  ] && usage
[ "$ADMIN" == "TRUE"  -a "$NORMAL" == "TRUE"  ] && usage
 
if [ $(id -u) -ne 0 ] 
then
    echo "You must be root to run this script!"
    exit 2
fi
 
[ "$GECOS" != "" ] && ARGS="-c $GECOS"
 
if [ "$ADMIN" == "TRUE" ]
then
    if ( ! isUserExits $USERNAME )
    then 
        createNewUser -s $USRSHELL -g $ADMINGROUP -d $ADMINDIR $ARGS $USERNAME
    else
        echo "Username \"$USERNAME\" exists in /etc/passwd"
        exit 3
    fi
fi
 
if [ "$NORMAL" == "TRUE" ]
then
    if ( ! isUserExits $USERNAME )
    then 
        createNewUser -m -b $BASEDIR -s $USRSHELL $ARGS $USERNAME
    else
        echo "Username \"$USERNAME\" exists in /etc/passwd"
        exit 3
    fi
fi
 
exit 0