Changing opacity of silhouettes

Hi, Using Daniel Shiffmana's MinMaxThreshold tutorial, I was able to change the colour from red to blue to green based on their distance to the Kinect. I would like to make a wall where when 2 people walk past each other, their silhouette colours mix. I tried to play with opacity with a background image but wouldn't mix 2 different silhouettes detected by kinect. Should I use blog detection to get the kinect to detect multiple people and how would I do this? I am using Kinect2 with Processing3 and seems like SimpleOpenNI doesn't work for Kinect2? Thanks!

Here's the code:

 import org.openkinect.processing.*;

// Kinect Library object
Kinect2 kinect2;

//float minThresh = 480;
//float maxThresh = 830;
PImage kin;
PImage bg;

void setup() {
  size(512, 424, P3D);
  kinect2 = new Kinect2(this);
  kinect2.initDepth();
  kinect2.initDevice();
  kin = createImage(kinect2.depthWidth, kinect2.depthHeight, RGB);
  bg = loadImage("1219690.jpg");
}


void draw() {
  background(0);

  //loadPixels();
  tint(255,254);
  image(bg,0,0);
  kin.loadPixels();

  //minThresh = map(mouseX, 0, width, 0, 4500);
  //maxThresh = map(mouseY, 0, height, 0, 4500);


  // Get the raw depth as array of integers
  int[] depth = kinect2.getRawDepth();

  //float sumX = 0;
  //float sumY = 0;
  //float totalPixels = 0;

  for (int x = 0; x < kinect2.depthWidth; x++) {
    for (int y = 0; y < kinect2.depthHeight; y++) {
      int offset = x + y * kinect2.depthWidth;
      int d = depth[offset];
//println(d);
//delay (10);
    tint(255,127);

      if (d < 500) {
        kin.pixels[offset] = color(255, 0, 0);

        //sumX += x;
        //sumY += y;
        //totalPixels++;

      } else if (d > 500 && d<1000){
        kin.pixels[offset] = color(0,255,0);
      }  else if (d >1000 && d<1500){
        kin.pixels[offset] = color(0,0,255);
      } else {
        kin.pixels[offset] = color(0);
      }
    }
  }

  kin.updatePixels();
  image(kin, 0, 0);

  //float avgX = sumX / totalPixels;
  //float avgY = sumY / totalPixels;
  //fill(150,0,255);
  //ellipse(avgX, avgY, 64, 64);

  //fill(255);
  //textSize(32);
  //text(minThresh + " " + maxThresh, 10, 64);
}