Soldiers are also in the scheme (7)
I believe the answer is:
platoon
'soldiers' is the definition.
(I've seen this before)
'also in the scheme' is the wordplay.
'also' becomes 'too' ('too' can be a synonym of 'also').
'in the' is an insertion indicator.
'scheme' becomes 'plan' (I've seen this before).
'too' put into 'plan' is 'PLATOON'.
'are' is the link.
(Other definitions for platoon that I've seen before include "Company's subdivision" , "Infantry unit" , "Small body of soldiers" , "Subdivision of a company" , "Military group" .)