The clusterer is used for combining closely positioned placemarks in a group (cluster).
The clusterer is implemented by the Clusterer class. The clusterer options can be passed to the constructor as parameters: the style of the cluster icon, the size of its cell, and so on. For the list of available options, see the corresponding section in the reference guide.
To add geo objects to the clusterer, use the add method. Either a separate geo object or an array of geo objects can be passed as the parameter.
The example shows how to change the color of the icon or cluster on mouse hover.