Arrangement to stop behind Saxony's borders (6)
I believe the answer is:
system
'arrangement' is the definition.
(I know that arrangement can be written as system)
'stop behind saxony's borders' is the wordplay.
'stop' becomes 'stem' (stemming is a kind of stopping).
'behind' means one lot of letters go next to another.
'borders' means to remove the middle letters (only the edge or border letters remain).
'saxony' with its middle taken out is 'sy'.
'stem' put after 'sy' is 'SYSTEM'.
'to' is the link.
(Other definitions for system that I've seen before include "Functioning set of interactive parts" , "Set of interrelated parts working together" , "Group of elements functioning as whole" , "Method of organization" , "Organized scheme" .)