In a corporate environment it is very useful to share a calendar, permitting others to see when you'll be in a given site, or in which meetings, but often there are attachments that contain priviledged information.

In a large organization it is not practical to explicitly share with certain individuals, so how do you secure the attachments but share the view of meetings, or at least meeting titles?

Here are a couple of quick ideas that may or may not work in your situations

Password Protect the documents

The main problem with this method is that either the password is used too much and everyone knows it, or there are too many passwords to remember and people have a hard time opening the documents.

Store the documents on a Server, and provide links in the Meeting Request

You could create groups based on criteria (Director / Manager / Supervisor / ...) and store the documents in the specific folder created for each group, or in the lowest level required provided that everyone above them also had access to that folder.

Mark the Confidential Meetings as 'Private'

Using this method, you could share your calendar with everyone, but only allow specific employee's (Secretary, Administrative Assistant, ...) access to view the 'Private' meetings.