Using mirrored RAID (RAID1) drive with multiple MBPs running Yosemite?

With apologies if this is a dumb question, but once a HD (a LaCie TB drive with two 500GB HDs) is set up as a mirrored RAID using Disk Utility, can I use it with two different Macs (both will be running Yosemite) or only on the Mac that I've used to create the RAID? On top of TM and BackBlaze, I want to use it to back up critical files from time to time on both machines and store it separately from where the computers are located. 500GB is enough storage (mainly want to preserve photos and some docs; everything else is replaceable) for both computers, and I thought that a mirrored RAID would be most secure.

I thought about encrypting the HD, but not sure how to do that if I'm using it on two different computers, unless there's a program outside of OS X that can do that. If anyone has a recommendation, I'd appreciate that, too.

Thanks in advance.

 

Thanks very much! I'll do a little experimentation to figure out the best solution for me.