title: Leaflet MarkerCluster: Is it possible to open multiple cluster-groups?
body: <p>I have recently started working with leaflet. I found the great plugin leaflet markercluster. I am currently trying to open several clustergroups at the same time. Unfortunately I can't find anything on google. </p>
  
  <p>I have several cluster groups and draw connections from one marker to another. The user should be able to open both cluster groups to which the drawn line goes:</p>
  
  <p><img src="https://i.stack.imgur.com/P8fLH.png" alt="My example"></p>
  
  <p>Therefore my question: Is there a function for this that I have to switch on or is opening several groups at the same time not provided at all?</p>