Deleting individual centermark from a centermark group

I would like to like delete individual centermarks from a centermark group.  Interactively in SolidWorks when I select a centermark that is part of a group and press the delete key it only deletes that instance in the group.  However from the API it appears that the reference is to the entire group and if I use the CenterMark.Select method and do a Modeldoc2.EditDelete call it deletes the entire group.  When I recorded the macro of the keyboard delete it uses SelectByID2("DetailItem342@Drawing View1",... the same selection in the API using the CenterMark.GetAnnotation method returns DetailItem334 which I assume is either the first centermark in the group or a reference to the group (I suspect it's the first centermark in the group because it returns a type of CenterMarkSym).

My goal is delete any dangling centermarks for a DriveWorks automation project.  (The DriveWorks delete dangling dimensions does not get the centermarks that are left dangling.)

SolidworksApi/macros