The new cat wishes to mark its territory by scratching. He is choosing objects that haven't been marked before to claim them for his own. The other cats don't agree and reclaim them.
If you spray the furniture with feromones (Feliway spray), they will have a general smell of a cat 'nest', the kind of smell produced by happy, relaxed cats, marking their own safe haven. That way, the furniture has already been 'marked' and need not be marked anew by each individual cat.
It no longer smells like the territorial marking of an individual cat, it 'smells like home', and cats don't mess up the smell of home.
You can use Feliway also to stop cats from urinating to mark their territory.
I have been using it for over a decade, and so far, it has always stopped my cats from ruining my home.