Well I got my answer here NVIDIA TITAN RTX is Here
MULTI-GPU SCALABILITY - NVIDIA TITAN RTX NVLink Bridge
The TITAN RTX NVLink™ bridge connects two TITAN RTX cards together over a 100 GB/s interface. The result is an effective doubling of memory capacity to 48 GB, so that you can train neural networks faster, process even larger datasets, and work with some of the biggest rendering models.
But it is already out of stock and even Quadro is out of the picture because that card costs a whopping $9000 (now Price) which is the budget of my whole system.
I will have to keep looking for a GPU. 
edit: At some sites, Titan is getting sold for about $2500. Hopefully, by the time I am going to buy, the price will drop further, as ETH mining is getting stopped in 2022 and Titan supports ray tracing. So it looks more likely I will buy Titan, though I will do some more research in the meantime.