Once you assign the Portfolio page template to a page a new "Portfolio Settings" box is available below the edit post... http://cl.ly/Riwg
This enables you to not only customize how the items are displayed but also which groups to pull from.
You create sub groups so that each portfolio page will have seperate filtering links. For example, you could have a Photography group with Weddings, Nature and Landscapes as sub groups. Then select to show Photography as the group in the portfolio settings and you now have a Photography-specific portfolio page.
5:17am on October 2, 2013