You can now send emails to a set of contacts based on the email label. For example if you have created a custom label named "His Emails" - then you can send a message to just those emails.
1. Go to Messages / Send Message and choose Message Type = Email. Select Recipients and click the dropdown. Here you will see options to email all contacts, all users, and then each group that you have set up. Now you also see all of the email labels that you have set up in your directory. Select who you want to send the message to and click on it.
2. Once selected, you will see the list of those the email will be sent to. Click "Compose Message" and create your email and then click "Send Message."