CCC and cloning partitions

Hello

I was wondering the capabilities of Carbon Copy Cloner. I've already used it, and it is fantastic. I am runing it on a Mac Pro with 4 drives (I'll call them drives A, B, C, and D). My question is: can CCC clone a partition on drive A directly to a second partition on drive A, or do I first have to clone it to a partition on drive B, and then from drive B back to the second partition on drive A? I have decided that I want to have 2 partitions with the same programs, but one as Snow Leopard (for Rosetta), and the other for Lion. So I would start with 2 SL partitions, but update only one of them to Lion. So it would be triple bootable between SL, Lion, and XP. Would this work?

Also, can describe how SheepShaver works?

Thank you so much!