Strategy also included a group of soldiers (7)
I believe the answer is:
platoon
'a group of soldiers' is the definition.
(I've seen this before)
'strategy also included' is the wordplay.
'strategy' becomes 'plan' (I've seen this before).
'also' becomes 'too' (synonyms).
'included' is an insertion indicator.
'plan' placed around 'too' is 'PLATOON'.
(Other definitions for platoon that I've seen before include "detail" , "Soldiers under lieutenant" , "Military group" , "Small body of soldiers" , "part of company" .)