Networking across borders: from ancient Greece to today

Imagine a network of people living in different states who acted as intermediaries for other countries, helping to sustain bonds of interest and to reduce conflict. Imagine these were appointed, unlike ambassadors, not by that country but by the people of the other state. Imagine that while this brought some material reward to the intermediary, it was mainly done for reputation. Sounds like something worth a kickstarter or foundation funding perhaps?