How to disable mouseover infobox over the spiderfier marker?

[benderlidze]

I am adding this event on every marker and want to disable infobox over the spiderfier marker/icon, just over the marker that are inside the spiderfier. Is there a wat to do so? Thanks

google.maps.event.addListener(marker, 'mouseover', function() {
		    ibLabel = new InfoBox(myOptions);
                    ibLabel.open(map);
});

Is there any difference between simple marker and spiderfier? any field in props that I can filter it with?