I have been successful in showing several nodes as markers on a Gmap.

This works as intended, but I want to go beyond that.
I would like some markers to be visible only at zoom levels specified in their nodes, I mean that some markers should be visible starting at zoomlevel 8, and others only from zoomlevel 12.

Using a google API marker manager, I can do that, but how do I do it in Drupal?

Another requirement is that some markers should be shown with their infobubble (or html label) visible by default, and other markers should not be displayed with the infobubble or label.

In principle, the above requires control over which data fields are transferred to the marker manager. Who has an idea of how to do this?

thank you :-)