User-specific Time Machine config
Unfortunately that is not the function of the Time machine.

Time machine does not only backs up all users files, but also the operating system, so you can restore from it.

“Time Machine is a backup utility, not an archival utility, it is not intended as offline storage. 

I would suggest you use separate disk for backing up individual users files.

The users home folders will be in the /Users/

To backup, use Disk Utility (in /Applications/Utilities/) to backup the user home folder.


Login as a local administrator, but not as the user account you want to backup.
Launch Disk Utility.
Choose File » New » Image from Folder...
Select the user's home folder /Users/[username].
Save the disk image to your backup drive.
Enter an admin username and password when prompted.