How to block group of users to use zimlet

[ohm_g7]

I have one zimlet and I want some users cannot use this zimlet.
So I create COS and check out the zimlet.
I config some user I want to block use this COS.
and I restart zimbra

I used this command for check zimlet list
# zmzimletctl listZimlets
I am not see the zimlet in list of COS


when I log in as user I block again,I still use the zimlet
I not know how can I do?

Please tell me
Thank you for reply