Focuses occasionally tells something like "if something happens"

What is my question is the part of the focus tree, that ends with asking help from Gondor. What must happen to activate this? We tried to go for Mordor and Gondor and nothing happened. What is the trigger?

Follow up question is, what actualy happens afterwards, but we will try that on our own.

Also a suggestion for this type of focuses, if something happens, than it will trigger this - maybe describe it a little bit better.