The map automaticly combines nearby nodes (depending on zoom factor). In my case it is really unpractical, because there is enough place to show every node specific.
I added an example.
File outerZoom.png shows Köln, Münster, Düsseldorf and Dortmund as one sign. File innerZoom.png (one step zoom in) shows Köln and Düsseldorf as one sign and Münster, Dortmund as single signs.
A solution to configure this aggregation factor would be an advantage.