how to merge two or more pins to centerlocation in map of android

Hi all I have created a map where i am pu开发者_Go百科tting multiple pins using overlays. i want to merge pins when there pixel distance will be approx invisible while zooming out and i want to reverse action i.e. saperate pins while zooming in. i have list of location with latitude and longitude where i am displaying pins.

Any logic, code samples, tutorial link.

i am completely stuck plz help me!!