Can PDFNet SDK recognize 'group' of *.ai file?

I’m using ‘ElementReader’ to extract vector information of .ai file (Adobe Illustrator).

I figured out ‘e_marked_content_begin’ means ‘Layer’ of .ai file.

However, it seems that there is no way to recognize ‘group’ of .ai file.

I know ‘e_group_begin’ is not same as Illustrator. It is just graphic state.

Is there anyway to recognize ‘group’ of .ai file?