Now there's the challenge!
Why not have a Tv talent show to find a unifying national anthem.
Surely, some genius wordsmith could produce lyrics that please almost everyone( well, 99.9%).
And, of course, other counties have strong regional differences ( Spain, for example, with Catalonia and the Basque region)
Come to think of it, I don't think Spain's national anthem has any words!
Maybe, that was their solution to the problem!