Is it possible to hide certain properties in a class from displaying in the BPL visual editor?

Is it possible to hide certain properties in a class from displaying in the BPL visual editor, if you want to prevent drag and drop from accessing them or otherwise controlling or restricting their behavior?

Virtual document messages, such as EnsLib.HL7.Message, have hidden fields, such as Source, that do not show, presumably since the field list is rebuilt from the document schema. Setting the flag Internal, or XMLPROJECTION = "NONE" doesn't do it. Trying to follow the Virtual Document precedent to rebuild or edit the field list seems like a heavy list.