The magic number seems to be 10 networks. The grouping of networks changes with the zoom level of the map, unless you have several networks positioned in the exact same spot on the map (it sounds like this is the case for you).
When there are several networks in an area, they get grouped into a bigger marker on the map. Clicking on that marker causes the map to zoom in and display the networks separately (again, based on the zoom level of the map and the relative positions of the networks on the map).
Of course, you can see the network status in the 'Network/Network tags/Devices' panel that floats over the map. You can use network tags or network names to quickly filter the list.
For a high-level view, you can use the Network tags panel. If any networks are alerting, you will see the overall status for the tag reported as yellow or red.
I'm not sure why, but it took a long time for me to notice the little triangle to expand the network panel that floats over the map. I find that expanded view to be especially useful.
Otherwise, the only other option I see would be to reposition the networks so they are spread out on the map a bit. If you're depending on location information from the Scanning API, you definitely do not want to do this.
