locking down “normal” user rights after crating a custom content type object (dexterity on filesystem)

[binderup]

I have a site where I have a custom workflow (setting the status to published on creation) and a custom dexterity content type defined.
Creating new items works like it should, but I still have some issues when it comes to setting security.

In the product I have created on the filesystem I have set the permissions so that only managers, editors and reviewers are able. This parts works as intended

I would then like to be able to prevent the normal user/member from gaining access to @@sharing and actions after the item is published.

I have not found a way to go about this other than going to zmi -> security and then set specific rights for the sharing bit.

Is it not possible to set these rights in my product and only in relation to the custom item I have created?

/Peter