The one the could use, since it's sung by both traditions, and takes a knock at both varieties of bigots, would be the Old Orange Flute. Back to Gargoyle's suggestion - well, there is a fourth verse Peadar Kearney wrote to the Soldier's Song with the North-East in mind:

And here where Eire's glories bide
Clann London fain would flourish;
But Ulster-wide what e'er betide
No pirate blood shall flourish.
While flames the faith of Con and Owen,
While Cave Hill guards the grave of Tone,
From Gulluion's Slopes to Inishowen,
We'll chant a Soldier's Song.

But I think that's one for the back burner.