Point Cloud Library: Sliced points to custom colors

I'm using pcl and vtk library with Qt for point cloud visualization. My setup is as the below link http://unanancyowen.com/en/pcl-with-qt/

Now when we slice points ie, press 'x' and select a region by AreaPickingEvent and that selected sliced points become red colored. It's done by the following function

void PointCloudVisualizer::highlightPoint(std::vector<int>& slice)
    {
        if (slice.size()<1) return;

        for (std::vector<int>::iterator it = slice.begin(); it != slice.end(); it++)    {
            m_cloudLabel[*it] = SELECTED_POINT;//SELECTED_POINT = 1
        }
    }

   void PointCloudVisualizer::updateCloud()
   {
    m_pViewer->updatePointCloud<PointT>(m_pCloud, m_pColorHandler, m_sCurrentPointCloudId.toStdString());
    m_pPointCloudVisualizerUI->qvtkWidget->update();
}

//area picking event, after the points are sliced we call these 2 functions and the sliced points gets red
void PointCloudVisualizer::AreaPickingEventProcess(const pcl::visualization::AreaPickingEvent& event)
{
    vector<int> newSelectedSliceVector;
    event.getPointsIndices(newSelectedSliceVector);

    if (newSelectedSliceVector.empty()) return;

    // remove ground points
    vector<int> groundPointsVector;

    for (auto point : newSelectedSliceVector)
    {
        if (m_cloudLabel[point] != GROUND_POINT)
        {
            groundPointsVector.push_back(point);
        }
    }
    .
    .
    .
    newSelectedSliceVector = groundPointsVector;

    m_lastSelectedSliceVector = newSelectedSliceVector;
    .
    .
    .
    highlightPoint(m_lastSelectedSliceVector);//red color selected points
    updateCloud();
    .
    .
    .
    }

//other variables
    int* m_cloudLabel;
    PointCloudTPtr m_pCloud;

    //initializing m_cloudLabel
    m_cloudLabel = new int[m_pCloud->size()];
    memset(m_cloudLabel, 0, m_pCloud->size()*sizeof(int));

    m_pColorHandler.setInputCloud(m_pCloud);
    m_pColorHandler.setLabel(m_cloudLabel);
    //----------------------------------------

    const int DEFAULT_POINT =  0;
    const int SELECTED_POINT = 1;
    const int GROUND_POINT = 2;

Now if we pass GROUND_POINT it becomes blue color, which is used for Plane detect or threshold.

Now my requirement is to color the sliced points as the user defines it. How can I apply my custom color to the sliced points by pcl::RGB.

Any suggestion is appreciated!!

The point cloud handler maintains a color LUT(look-up table) for coloring the sliced points. Updated the color LUT and called highlightPoints, where SELECTED_POINT index updated as the user selects the color.