How can we stacked wedges of outer ring one above another using WedgeStackChart of axiis?

[Gannesh]

Hi All,

Firstly i wanted to Thank you for creating awesome charts.

I am very new to axiis. I am trying to create charts as shown in this
link using Flex.
http://www.digitalsurgeons.com/facebook-vs-twitter-infographic/

Axiis WedgeStackChart is some what similar to the above charts. but it
has only two rings and the outer ring's wedges are plotted side by
side.

What should i do to created charts as shown in the link.

Thanks in Advance!

GB