I was having some issues with getting the grouping to appear correctly on my site. I had two groups set up and no matter what I did, all staff would appear on both pages.
What I had done was copy the shortcode using Ctrl-C directly from the Usage page of the plugin and then pasted it into the visual editor of wordpress.
What this did was add all sorts of extra code to the shortcode when viewed in Text view.
Once i had the code entered correctly in Text view ... all worked flawlessly.
Just thought that someone might be helped by this.