That feature is not supported.  It's all or nothing right now.

I'll bet Seabass will be here in a minute stating that he'll pass it on to Jeff.
 

create one dock > go to Object Dock Settings > Themes Tab > under "Backup" click "Save Current Dock" > give it a name like Dock 1 or something.........

back to Dock Settings > My Docks > create new..... > delete first dock > get the new one like you want and repeat above steps but name it Dock 2 or something.......

repeat process until all individual docks are created and saved, then use "Load Previous dock......" to switch back and forth among them.......

Geez folks, if all else fails, use auto-hide!

Thanks, Lantec. I thought I could save each version but wasn't sure if it would work. I tried saving something in the past and it didn't seem to work but I'll try this and see if it works. I thought about auto-hiding a dock but would rather not have to do that.