add two secure zones to TI?

I'm using TI 8 (build 800) to backup our fileserver.
For this I initially planned two removable Harddisks, so that only one HD is connected to the server at a time. The other one could then be located in a "secure" place.
My concept was to use two generations of backup. But as TI only allows one secure zone, I am a bit helpless on my concept...

As I am very convinced about the concept of the "secure zone", I set up a secure zone on one of the HD. But as I cannot add another "secure zone" on the other HD, I am lost now...
... I could of course use one harddisk permanently for fullbackup and incremental backup in its secure zone and the other one periodically for fullbackup in a *.tib file... But I am not very convinced on this one...

Or is there a trick on how to use two secure zones with external Harddisks?

 

An alternative would be to use one or no SecureZone. As long as you will be removing the drive to a secure place (excellent plan), why not just put the image on the drive in a normal partition. This has the advantage that you could burn it to DVDs or copy it to another location if there was a reason. If the image is stored in a Secure Zone, you cannot copy it or burn it to optical media.

The Secure Zone is very useful for people with only one hard drive because it provides a place to put images without having to use other software to repartition the hard drive, and repartitioning raises other issues with the bootability of restored images. It's excellent for having an image quickly available in the event of a bad hardware or software installation, spyware or virus attack. However, in your case, I'm not sure of the advantage over saving the image on a normal partition of the removable disk.