ECP: Hide recipients mailbox that not managed by a user

Hello,

we use Exchange 2013, we want to permit an user to manage  récipients present in an OU.

we created a Role group, and in Write scope we put the name of the OU mydOmain.com\myOU

and we selected the role and the members

but when my user is logged to the EAC , he see all récipients , not only récipients in this OU.

how i can do to limit the view at only recipient in the OU?

thanks by advance

Mbark