How to show up 2 users on a gmap, who have exactly the same location

I have the same issue, but with nodes, not users.
I have a test case with 2 modules with exactly the same location:
http://foutparkeerders.be/kaart
Zoom into Gent, Voskenslaan - a street in the SW of the city. There are 3 nodes in that street: one near Schoonmeersstraat and two with identical location near Tuinwijklaan. These two nodes with identical location are:
http://foutparkeerders.be/node/5
http://foutparkeerders.be/node/50
Only node/5 is shown in the popup when I use no marker manager.

I have tested the following marker managers:

• Google's GMarkerManager
  No clustering
• Gmaps Utility Library MarkerManager
  No clustering
• Jef Poskanzer's Clusterer
  Shows list of nodes in a popup
  My settings:
  Activate on: 2 or more markers
  Cluster on: 2 or more markers
  Lines per box: 10 at most lines
  Result with popup mode Zoom to Cluster: cluster until the last detail (GOOD), no popup (BAD)
  Result with popup mode Original: cluster until the last detail (GOOD), cluster popup only shows location icons, not the node fields that were defined in the View (BAD), no links to the nodes (the links were defined inside the View) (BAD)
• Martin Pearman's ClusterMarker
  Shows a cluster until the last but one zoom (BAD)
  On the final zoom, only the first node is shown (BAD)
  Customizable cluster message with %count variable (GOOD)

I would like to see a cluster that works mostly like Jef Poskanzer's Clusterer, with the following features:

• cluster until the last zoom
• popup when marker is clicked
• marker shows list (UL) of nodes with the fields as defined in the View
• It is up to the user to define a field in the View that provides a link to the node
• Customizable cluster message with %count variable (as in Martin Pearman's ClusterMarker)

EDIT: see http://drupal.org/node/530328#comment-1919830
It makes more sense there. Sorry for the duplicate.