We have a JIRA installation that is used by many different projects between our company and many different costumers. When using the "Send E-mail" form under "Administration -> Options & Settings" and sending an e-mail to all groups the recipients e-mail addresses is in the "To:" header.

It should be possible to select a checkbox saying that you which to send the e-mail using the "Bcc:" header instead.

This is very important because we have many different costumers.

/watson