multiple copies

I have a basic question in my mind, and need you to help me out.

 
I wanted to make two copies of the backup as show in the screenshot above. I have one STU and 4 drives in the tape library. My questions are following:
1. when making two copies, will data be written to two different drives, or could be written to 4 different drives. If it could be 4, where and how could it be done?

2. Assume each copy has their own set of tapes, how do I know one set of all tape ID’s, and therefore I can eject the whole set, and then send them to offsite?

Your advices are greatly appreciated.