Split up or separate into parts (6)
I believe the answer is:
divide
This clue is a double definition.
'split up' is the first definition.
(synonyms)
'separate into parts' is the second definition.
(I've seen this before)
(Other definitions for divide that I've seen before include "Separate into portions" , "Part" , "Seperate, split" , "Bisect" , "Partition. separate" .)