now i tried

chgrp try /users/abc/
ls -l | grep abc
drwxr-xr-x 13 abc try 1024 Jun 21 22:50 abc

i have the effect of the above chgrp command only for /users/abc/ the file that i had specified in chgrp

but still
the file /users/abc/sub is in req group

could somebody help me with this?