Hey Robyn,
There unfortunately isn’t much extra that can be done here – if the location-based filtering in the Filter Bar add-on is not enough, then the strength of the location filtering would be in the hands of that interactive map plugin you mentioned.
You could filter Venues by various components of their address manually, e.g. by their City, or State, or Country, or even zip code if those are provided. But as for plotting those specific grouped events on a map, that’s something that would unfortunately take a significant amount of custom coding.
Let us know what you think here, if my reply here wasn’t specific enough let me know what other information you’d be curious to know!
Thanks Robyn!