Differenciate between onMarkerClick and onClusterItemClick event in Android

I am using google map v2 with 1000 plus markers being fetched from web service. So for this reason i am using map clustering. I am showing info window onMarkerClick but the problem is that when the user click on cluster it shows info window because onMarkerClick event is triggered. I want to zoom further when cluster of markers is clicked. There is onClusterItemClick event but its not working with onMarkerClick. Any feasible solution is appreciated in advance.

Thanks