You can do that with the Experience Add-on
Cluster Map Markers
Cluster Map Markers is available as part of the Premier plugin included with the Premier Subscription for Store Locator Plus or the Enterprise level of MySLP. Cluster Markers show a single map marker graphic (circle with number inside it) when two or more (you set this number) markers are within close proximity to one another on the current map view. As a user zooms in on the cluster, the clusters break apart to show the individual markers. When zoomed out the individual location markers combine into a single marker graphic with the count of locations represented by the graphic shown in the center. You determine the default radius and minimum number of locations before cluster map marker is engaged. Your “center map at” and default radius setting will effect where the map center is located.
Turn On Cluster Markers
Go to the Store Locator Plus : Settings / Map and look under the Appearance section for “Enable Cluster Markers”.
Read the Store Locator Plus news articles about Cluster Map Markers.
Selecting and Customizing your Style
Store Locator Plus Appearance
Store Locator Plus comes with a variety of styles to provide a basic style framework that will attempt to match your locator page to various WordPress themes installed on your site. You can see the list of Locator Styles under the Store Locator Plus Settings / View panel. The inner slide bar will show you more.
