protected function fillVariables()
    {
        $variables = array();
        $internalVariables = array( 'ResponseGroups' ); // Expected variables

        foreach( $internalVariables as $internalVariable )
        {
            if( isset( $_GET[$internalVariable] ) )
            {
                // Extract and organize variables as expected
                switch( $internalVariable )
                {
                    case 'ResponseGroups':
                        $variables[$internalVariable] = explode( ',', $_GET[$internalVariable] );
                        break;

                    default:
                        $variables[$internalVariable] = $_GET[$internalVariable];
                }

                unset( $_GET[$internalVariable] );
            }
            else
            {
                switch( $internalVariable )
                {
                    case 'ResponseGroups':
                        $variables[$internalVariable] = array();
                        break;

                    default:
                        $variables[$internalVariable] = null;
                }
            }
        }

        return $variables;
    }