I'm not entirely sure I understand.
You want ambassador from Realm A to be able to talk to ambassador from Realm B, without going through the ruler?
First of all, Contact Management, which is active on all continents, should allow the ruler to send each ambassador's contact details to the other, and enable to them to talk directly that way.
Second of all, on testing, all Ambassadors now have an option to message all the ambassadors of another specified realm.
