Bash argument with multiple values

Question

My situation is the following: I want the script to be able to be able to receive multiple value parameters. For an example

./script.sh -u username -p password -h hostname -pk file1.zip file2.zip

The way it is made it can receive only one file as an argument e.g ./script -pk file1.zip

I'm not sure how make it so $PACKAGE variable can receive multiple values. Not a pro on bash, so would appreciate some ideas :)

while [ "$1" != "" ]; do
    case $1 in
   -h | --host )       shift
                              HOST=$1 ;;
   -u | --username )   shift
                              USER=$1 ;;
    -p | --password )  shift
                              PASSWORD=$1 ;;
    -o | --out )       shift
                              OUT=$1  ;;
    -pk | --package )  shift
                              PACKAGE=$1 ;;
    -g | --group )     shift
                              GROUP=$1  ;;
    -n | --name )      shift
                              NAME=$1  ;;
    -h | --help )      help
    exit
                ;;
    list )             ACTION="list"
                ;;
    "install" )        ACTION="install"
                ;;
    "upload-install")  ACTION="upload-install"
                ;;
    upload )           ACTION="upload"
                ;;
    download )         ACTION="download"
                ;;
    delete )           ACTION="delete"
                ;;
    * )                usage   exit 1
    esac
    shift
done