Burning unique content to Multiple Optical Drives at Once

I'm trying to look for the best possible solution for this situation.

I have one Mac Pro and 3 External Optical Drives. I'm trying to manage and back-up strictly data to essentially 4 Optical Drives.
Its roughly 16GB and should Span across 4 DVD Discs no issue.

However I noticed with Toast, it does Spanning but unique content is contained to One Optical Drive. If you have multiple drives, it will just Make Duplicates and not Span unique content to it.

So im trying to figure out how to send all this unique data spanned across 4 drives without duplicating, simultaneously.


Mac Pro (Optical Drive 1) - Unique Content Pt. 1
Optical Drive 2 - Unique Content Pt. 2
Optical Drive 3 - Unique Content Pt. 3
Optical Drive 4 - Unique Content Pt. 4

Thanks!