Correctly handle clustering when markers are placed identically and overlapping

Question

I am using GoogleMaps and the google-maps-ios-utils clustering library. I am in situation where I have couple of markers(annotations) in exact same location. Now I want user to see them all, but they are under each other.

Lets say I have 4 markers on location lat: 37.331829 and lng: -122.031169

Now what would be the best to show all three markers in maybe shape like this(this circle is imaginable):

I think something like this can be achieved using their GMUClusterRendererDelegate function but I do not know how:

func renderer(_ renderer: GMUClusterRenderer, willRenderMarker marker: GMSMarker) {}

I found many solutions for JavaScript but nothing for swift. I think this is the best example to describe myself.

Any soltion with even Apple's MapKit is welcome. I may switch.