For such situation, Bccthis can be very useful. It claims to add context to email by adding private messages to selected recipients. It could be easily used with Gmail by a firefox plugin. Bccthis Adds Private Messages for Some in Mass Emails
The addons adds an extra composition box at the bottom of the Gmail’s Compose view. Here you can add that private message and specify which recipients from the ‘To’ or ‘CC’ field should receive that secret message. All recipients will now receive normal mails that were intended but Bccthis specified recipients will get 1 extra mail with private information. Bccthis specified recipients will get 2 emails so that they can respond to the original email and protect the sender from accidental reply to all. If a recipient is added in BCC field, only one integrated email is sent. Gmail users can use Bccthis with a Firefox addon. It is also available for outlook and blackberry for other emails. So, why send extra mails when this clever and free addon is here to help. Note 1: Recipients need not to download Bccthis addon to view private messages. Any email client or mobile device will display them. Note 2: Bccthis plugin for outlook gives you better control over the private messages compared to gmail addon. It also has various settings and customization features. It is better to use outlook plugin, if possible.
