automatically set Span in swift 4 mapView

hey there,


i have different groups of custom annotations on a map and i want to set the span of my mapview depending on wether or not the user can see a specific group of annotations --> e.g. 5 green annotations and 4 red ones; the map automatically zooms out until at least one green annotation can be seen, while still centering on the userLocation; it ignores the red ones

Is that possible?


Thanks a lot,

Gus