Stay in a formation of IRA men (6)

I believe the answer is:

remain

I'm a little stuck... Click here to teach me more about this clue!

'stay in a formation' is the definition.
'remain' can be an answer for 'stay' (I've seen this in another clue). I'm unsure of the 'in a formation' bit.

'of ira men' is the wordplay.
'of' indicates an anagram (the answer comes from or 'of' the letters).
'ira'+'men'='iramen'
'iramen' is an anagram of 'REMAIN'.

Can you help me to learn more?

(Other definitions for remain that I've seen before include "Marine (anag)" , "Stay behind" , "Continue in position" , "Stay (in position)" , "Stay on when others have left" .)

I've seen this clue in The Globe and Mail.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.