Files duplicated within shares under a single dataset?

[generaltablet]

I’m running 8.2.0 RC1. 4 x 2TB disks as RAIDZ.

Code:

volume
    dataset1
        share1
        share2
    dataset2
        share1
        share2

Shouldn’t I be able to set it up this way?
I can’t. setting it up this way duplicates the files between the 2 shares of a single dataset.
I want to do it this way because I want to have snapshots of all shares under dataset1 and no snapshots of shares under dataset2.

Thanks. --Steve