How to access screen elements of main screen from the sub screen in PBO?

Hello everybody,

Is that possible to access dynprofields of main dynpro from subscreen? The main Dynpro call subscreen with command:

CALL SUBSCREEN <name> INCLUDING <report_name> <dynpro_nr>

I would like in PBO module of subscreen dynpro to iterate the SCREEN table of the main screen and make a field active based on one of the value of the subscreen element. I want to use Loop at Screen of main screen inside a subscreen.

Thanks & Regards,

Abhishek