Hello,
You mean to say that you want to hide selection screen field's based on user logged on?(Sorry if i'm wrong.)
If so,please check this.
at selection-screen output.
if sy-uname = ' username'..............
loop at screen.
case screen-name .
when 'field names/parameter names'.
screen-invisible = 1.
screen-active = 0.
modify screen.
endcase.
endif.
and vice versa.
Thanks
Katrice