the user wants to send an email securely to a certain list of people.
the people who receive the email must not allow their delegates see the contents of the mail.
only the person on the list must be able to open the email not delegates.
Some delegates have owner rights and can see private mail of their boss.
Is there a way that mail can be sent from one person to another with only that person able to open that email. Not their delegates.
http://technet.microsoft.com/en-us/library/dd996640(v=ws.10).aspx
Windows Live ID is a free, cloud-based email and identity service provided by Microsoft that allows anyone to open an account and use it for email and other services. Microsoft provides an AD RMS service for Windows Live ID accounts and this service can be integrated with any organization’s AD RMS platform, via a trust.
However, this has limitation - This solution is applicable only in situations where the number of external users that need access to protected documents is relatively small and these external users do not need to create protected content, only to consume it.
More steps on how to setup for consumption
http://office.microsoft.com/en-us/outlook-help/help-protect-confidential-information-in-e-mail-using-irm-HA001180136.aspx
Also RMS setup if interested
http://www.simple-talk.com/sysadmin/general/getting-started-with-active-directory-rights-management-services-for-exchange-2010/