iOS Google Map API clusters and bounds

I'm struggling with Google Maps development at iOS and looking good simple example demo app Base requirements to get going 1) Written in objective-c and compiles successfully 2) Has working integration with Google Maps API 3) Map shows sample markers with lat and lng coordinates Actual need 4) App has one button - if pressed then it finds all the markers what are visible currently on screen and makes array of them. Markers what are out of the screen bounds are not included in that array 5) If there are markers colliding with each other then they are grouped into clusters and count of markers are shown in cluster ( example from javascript Google Maps API v3 [login to view URL] , I need same thing for iOS) This is probably really easy task for qualified iOS dev but I really appreciate your help. Thanks