Gmail – Changing subject line without splitting up the conversation

Gmail now has a feature to disable conversation view. Its under the General tab in settings. Unfortunately it disables conversations for the entire account. There's no way to selectively break conversations. The best you could do would be to use IMAP to access the problematic messages and rewrite them.

There isn't a way to auto-prefix subjects based on emailing a contact group. Note: This is different from Google Groups.

When you decide to email all/some people in a group, GMail will individually add each of those people to the To: line of the email.

Since I was on the kick, I tried setting up an email group (group@my-domain.com) in my Google Apps for Business account. And while you can add members/owners to the list from there, you cannot customize the subject line for Apps for business accounts either.

However, using the Google Email groups from within apps may solve your issue. You can set it up so that people are only replying to that group email (group_1@your-domain.com). This will make your replying easier and also make filtering a snap as well as not forgetting to include someone.