Limit - set one on a group of soldiers (7)

I believe the answer is:

militia

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'group of soldiers' is the definition.
'militia' can be an answer for 'soldiers' (I've seen this before). I'm not sure about the 'group of' bit.

'limit set one on a' is the wordplay.
'set' is an anagram indicator (instruction to set the letters).
'one' becomes 'i' (Roman numeral).
'on' means one lot of letters go next to another.
'limit' with letters rearranged gives 'milit'.
'milit'+'i'+'a'='MILITIA'

Can you help me to learn more?

(Other definitions for militia that I've seen before include "Fighting force of civilians" , "Territorial force" , "Army of non-professional soldiers" , "Troops" , "Group of citizen soldiers" .)

I've seen this clue in The Daily Express.

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