Email encryption within a group

There is a group in Symantec Encryption management Server. Say, "ABC"
The group has some members.

Please advise:-

1. How to configure the policy in such a way that when the users within the group ABC send emails to each other, the emails should be encrypted automatically?
2. Can we not have the encrypt button in outlook and still get all the emails encrypted between the users of this group?
3. How can we disable the notification box that appears saying the mail was sent secured ot not?