Hi Denis,
You can always query the posts that have the Google Map field and then loop it and show it on the map.
To query the posts, please take a look at this page: https://codex.wordpress.org/Class_Reference/WP_Query.
To see how to add it on the map, please take a look at this page: https://www.advancedcustomfields.com/resources/google-map/.
Hope this helps.
