$local:prev = "";
zfs list -o name,used,avail,refer,canmount,mounted,mountpoint $args |
    grep -v 'docker/' |
    ForEach-Object {
        $local:tmpPrev = $_ -replace '^(\w+(\W\w+(\W\w+)?)?).*','$1';
        if( $tmpPrev -notmatch "^$prev" -and $prev -notin ('','NAME') ) {
            '-----------------'
        };
        $prev = $tmpPrev;
        $_
    }