Since it looks like you already have a filter action setup, have you thought about applying some sort of rounding to your lat / lon values, removing your Name field from detail on your map, and then just having a user click the mark to see the names show up on the right?
See the attached workbook for an example. Obviously this wont be perfect, but it may help you get closer. You may also be able to use the rounded lat/lon on detail in your viz that has name and pass these fields in your action field. This way, you can keep the info in the viz as well as potentially capture the names that may overlap when you get results in your second viz.
Maps.twbx 99.1 KB