Persistent RAM disk referencing pre-existing files on the hard drive

Can a persistent RAM disk be created that references pre-existing files as the image files?

The idea is to create a RAM drive that is populated from and backed up with specified files (or possibly all the files in a specified folder). In other words, just exposed an existing set of disk files as RAM disk files, with no need to copy back and forth from the hard drive to the RAM drive (or the so-called image files).

It is impossible to have a RAM disk with some files appearing on it after startup without copying them there first from somewhere else.

RAM disks reside in RAM (obviously), and therefore cannot themselves store any data between shutdowns. The only way to have any pre-existing data on a RAM disk is to copy it there from some persistent storage like an image file stored on a hard drive. Likewise, it is physically impossible to update RAM disk image files on the hard drive without copying them back from RAM. Of course all this doesn't have to be done manually. There is a range of tools you can use to populate your RAM disk on startup (e.g. Robocopy or a backup/restore program). Then it can be set to back up the files back to the hard drive on schedule or on demand.

If the files are somehow merely "referenced" from a RAM disk while being physically kept on a hard drive, then there is no point in RAM Disk at all. The two main reasons for having a RAM disk are: to store temporary data on it that is guaranteed to disappear or shutdown, and to work with data located in RAM which is both very fast and spares the hard disk unnecessary wear.