There is a song which begins As I came in by Newry Town
Who do you think I saw?
I met the first battalion of the men from South Armagh
This is followed by a nonsense chorus or refrain.
Have you crossed the border?
And have you travellled far?
Did you meet the army on the road
Were they in armoured car?
If this is the song you're looking for I'll try to find out more. I think it's called "Crossmaglen" and it is, purely and simply, a rebel song.