Control cache priority based on mtime?

So I have a server that's going to get new files regularly. Those new files will be accessed by several people over the network early and often, then will not likely be used for a long time after that but will remain on the server.

What I would like to do is put the 20TB+ storage array that's going to hold these files behind a bcache device. With the bcache device it may or may not add the new files to the read cache before they're done being accessed for the initial time period where they are going to be accessed many times in short frequency. I would like to tell bcache to cache all new files of a specific file type until mtime = +X.

This is for performance reasons as well as to minimize unnecessary reads from the main array, reducing wear.

Is this possible or am I dreaming? I've thumbed through everything I can find on bcache and I've found little about fine grained control like this.