Tooltip that only shows nearby points?

[NicholasMerritt-eaton]

I'm making a chart setup that plots an arbitrary number of ScatterSeries, which means (in rare cases) there can be a large number of series. This results in a very tall tooltip at all times, even if some or most of those series aren't close to the pointer, as in the image below. (Note that this example is an exaggeration and isn't a real set of data that would all be on the same chart simultaneously.)

Is it possible to have a tooltip that only shows points within a certain 'distance' of the pointer? It seems like this would be accomplished by changing the HoverArea used by the series (or points?) to be a small circular area but I haven't been able to figure out how to do that.