Press hill of a peacemaker (8)
I believe the answer is:
mediator
'a peacemaker' is the definition.
(I've seen this before)
'press hill' is the wordplay.
'press' becomes 'media' (the press is part of the media).
'hill' becomes 'tor' (tor is a kind of hill).
'media'+'tor'='MEDIATOR'
'of' is the link.
(Other definitions for mediator that I've seen before include "Go-between, negotiator" , "Kind of arbitrator - one to admire" , "peacemaker" , "Negotiator between opposing parties" , "One intervening to settle a dispute" .)