The phrase "which unlike" is correct and usable in written English.
You can use it when introducing a contrast between two ideas. For example, "Unlike the classic model, these new headphones have wireless capability."
She points to her neck, which, unlike that of most Nuer women, is unadorned.
Which, unlike any other religion, slaughters and decapitates or enslaves all those who live differently".
He is also mulling a new album which, unlike his Bond covers, would be original material.
There's a cafe, too – which, unlike the shop, is only open between Easter and October.
Both agreed to allow religious toleration, which, unlike Valens, Valentinian maintained throughout his reign.
Talk story about the new Ivory Liquid, which, unlike the old Ivory Liquid, isn't white.
Signs of turmoil and slow growth among the Trump Super Pacs, which unlike campaigns can accept unlimited donations, are palpable.
The female clerk explained the three styles, which, unlike those at other stores, were simple and made sense.
China, which unlike Russia remains under Communist Party monopoly, is certainly no less an authoritarian challenge than Russia is.
But not in the Finger Lakes, which unlike other major hog-raising areas is also a prime vacation spot.
Chandler focussed on the modern industrial corporation, which, unlike Christensen, he studied comprehensively over time and across leading economies.
