Servers in general and letters sent Cci

Hello

I have a very general question about a company server (exact type of server
unknown)

I would like to know sth about a document which is sent out Cci to people in
the same company connected to the same company server.

In these circumstances, could anyone find out who has received the document
by 'interrogating' the server.

How far does cci protect the receivers of the doc in these circumstances?

Thanks

PS The document is a workers' newsletter sent out to people who have
expressed a wish to receive it but are worried about management finding out
that they have asked for it.