Bureau specialising in mediation? (6)
I believe the answer is:
agency
This might be a double definition.
'bureau' is the first definition.
(synonyms)
'mediation?' is the second definition.
(thesaurus)
'specialising in' is the link.
This may not be right. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for agency that I've seen before include "Business that serves other businesses" , "Function of one who acts for another" , "Through which something is accomplished" , "Intervention producing a particular effect" , "Office or business of one who does business for others" .)