Find or Match Specific Contacts when Addressing Messages

When addressing a message, Postbox will match contacts from the Address Book(s) as you type.

However, if you are attempting to match against common names such as "John", a large number of matches may return. 

You can more quickly jump to specific names by adding a "Nickname" in the contact card.  Find a message from that contact, click on the contact name, and then select "edit" from the pop-up menu.

If you are using the Postbox Address Book, select the contact and then click the Properties button in the toolbar.  Add a unique name in the Nickname field.

If you are using macOS, and have Postbox configured to use the Contacts app, you can then go into Contacts > Preferences > Template and add a field for "Nickname".

Be sure to Restart Postbox so that it can sync with the changes you made.