title: MarkerClusterer and the default icons
body: <p>I have a map with, say, 3 groups of markers (red, blue and green ones) that represent different kind of stores. </p>
  
  <p><img src="https://i.stack.imgur.com/uZU2V.png" alt="enter image description here"></p>
  
  <p>I need to group that multiple markers into a cluster, like MarkerClusterer does.</p>
  
  <p>But for the moment I don't know if there is some ways to work with heterogeneous types of markers.</p>
  
  <p>Let's say the simplest way is to group all markers regardless of its color when we unzoom. Is that possible to however to set a different color (red, blue and green specific) when the group is zoomed?</p>