Regarding smtpd_recipient_limit

[Joy]

Dear All,
                  I  want to restrict users to not send more than 5
recipient in TO/CC/BCC to external recipient so i have implemented one
relay server to restrict the same. I configured my relay server with
following line in main.cf

  smtpd_recipient_limit = 5

I reloaded the server but so far no success while all is running well mail
is being delivered through relay server to external recipient.

Please let me know what is going wrong.