To break up requires determination (7)
I believe the answer is:
resolve
This clue is a double definition.
'to break up' is the first definition.
(I've seen this before)
'determination' is the second definition.
(I've seen this in another clue)
'requires' is the link.
(Other definitions for resolve that I've seen before include "Firmly decide" , "bottle" , "Decide; firm determination" , "Settle; firmness of intent" , "Analyse" .)