Here are some decent wikipedia pages the Roundtable Groups.

https://en.wikipedia.org/wiki/Round_Table_movement

https://en.wikipedia.org/wiki/Milner%27s_Kindergarten

https://en.wikipedia.org/wiki/Chatham_House

https://en.wikipedia.org/wiki/Council_on_Foreign_Relations

https://en.wikipedia.org/wiki/European_Council_on_Foreign_Relations

https://en.wikipedia.org/wiki/Institute_of_Pacific_Relations

https://en.wikipedia.org/wiki/Carroll_Quigley

https://en.wikipedia.org/wiki/The_Round_Table_(journal)

https://en.wikipedia.org/wiki/Foreign_Affairs

https://en.wikipedia.org/wiki/Chatham_House_Rule

https://en.wikipedia.org/wiki/The_Inquiry

https://en.wikipedia.org/wiki/Advisory_Committee_on_Problems_of_Foreign_Relations

https://en.wikipedia.org/wiki/Committee_for_the_Marshall_Plan

https://en.wikipedia.org/wiki/The_Wise_Men_(book)

https://en.wikipedia.org/wiki/Independent_Task_Force_on_North_America

https://en.wikipedia.org/wiki/Round_Table_Conferences_(India)

https://en.wikipedia.org/wiki/Canadian_International_Council

https://en.wikipedia.org/wiki/Centre_for_International_Governance_Innovation

https://en.wikipedia.org/wiki/Indian_Council_of_World_Affairs

https://en.wikipedia.org/wiki/Australian_Institute_of_International_Affairs

https://en.wikipedia.org/wiki/Tragedy_and_Hope

https://en.wikipedia.org/wiki/Rhodes_Scholarship