Gray House by Mariam Petrosyan,
https://www.amazon.com/dp/B01JZAKPF0
It is a cult classic in its native Russian (fanfics, fanart, cosplay, the lot), and has nothing to do with the "physically disabled teens overcoming adversity" boilerplate that it's advertised with - or, rather, it has about as much in common with the real book as the eponymous three-story building has with what's going on inside it.
"My most important problem was destroying the lines of demarcation that separates what seems real from what seems fantastic", said Marquez - this book solves it, and how.
Also, the book club format is perfect for it, because there's so much hidden inside to dig out, and discussing the sudden discoveries is fun.
(full disclosure: I am the translator into English, and know it almost by heart - so if it's chosen, I'll lurk, but would be able to answer questions)
It is a long book though (300K words), and takes its time spooling up; things start happening in earnest only after about a quarter of the way through.
https://www.goodreads.com/book/show/...the-gray-house