Lightroom Desktop: Ability to specify multiple local storage locations

It would be great to allow the setting of multiple local storage locations for images.
I currently keep my older, archived pics on my NAS, and only retain the most recent photos on my local SSD due to space constraints.

I'd therefore like to nominate two local storage locations for my images.  Whether chosen by album, folder, or even just capture time, the ability to tell Lightroom to keep local copies of some photos in one location (fast SSD) and the rest somewhere else (slower NAS) would be very helpful. 

I definitely want local copies of everything, but I can't fit them all on my SSD, which today means everything goes on the NAS, which unnecessarily slows things down.

Thanks