How to get Time Machine disk to backup itself? How to get Time Machine disk to backup itself (ie, non-Backups.backupdb on the Time Machine disk)?

Specifically: I moved my /Users folder to a separate parition, a parition that also houses Time Machine backups (for my boot-SSD parition in /Users/Backups.backupdb).  I also want to Time-Machine backup the /Users/ folders, but Time Machine won't (thus far) let me backup folders/files on the same disk where the Time-Machines backups are stored.

From one standbpoint, it makes sense to keep physically-different disks.  (I employ multiple Time-Machine disks for this purpose, including for system above.)  However, most backup needs are not due to physical-drive failure, but a "logical/soft" fault (usually me accidently deleting files), and as such, enabling the backups above would prove quite valuable.
It sounds like you're trying to recreate something Time Machine already does via its "Local Snapshots" feature (see here and here for info).  Basically, all you need to do is configure your Mac to back up to an external drive, and then whenever that drive isn't available it'll make local snapshots instead (as long as there's disk space available).