How to export Textflow XML for Specific container control?

Question

I'm implementing a TLF control which has multiple text box each linked to one another using same textflow instance for all the containers. I need to export the textflow xml for Container 2/1. There is a way in TLF to export the textflow XML like this.

   private function getTLFString(textFlow:TextFlow):Object
    {
        return TextConverter.export(textFlow,TextConverter.TEXT_LAYOUT_FORMAT,ConversionType.XML_TYPE);
    }

but this will return the whole textflow, is there any way to get the selected containerController Textflow XML with formats/styles ?