Questions on filter driver of disk.sys

We are planning to re-implement our encryption/decryption
software to encrypt/decrypt some specific files.
What we are considering to do is:
First, on file system side, a filter driver is used to
handle the IRPs that are related to those specific files.
Second, on storage driver side, a upper/lower filter driver
is installed on the disk.sys. This disk filter driver will
claim certain disks and use them for saving some specific
encrypted files outside of the normal Disk Administrator.
Ideally, we want to make some disks disappear as far as
normal disk management is concerned and they should not
even appear in the Disk Manager applet. At the same time,
the kernel driver can recognize this disk and save the
specific files to this disk.

Is this possible to implement above strategy? If yes, where
is the start point to implement the filter driver for
disk.sys? What kind of request this filter driver need to
monitor? BTW, how can the file system filter driver and disk
filter driver communicate each other? Is VPB an only
bridge between file system and disk?

This probably seems like a stupid question, but any comments
or suggestions will be greatly appreciated.