When you use a Summary Link Web Part or field control to add links to a page, you may want to group the links by using group headers. For example, you can create a group with the group header External Links and add links to the group that point outside of your site.
On the Site Actions menu , click Edit Page.
Note: This step is not necessary if you are already editing the page.
In the Summary Link Web Part or field control, click New Group. The New Group Web Page dialog box appears.
In the Group Header Name box, type a name for the group. This name appears at the top of the list of links that you add to the group.
Note: When you create the first group for a particular Summary Link Web Part or field control, any exisiting links in the Web Part are added to that group. Additional groups that you create are initially empty.
For more information about using and configuring a Summary Link Web Part or field control, see the article Use and configure a Summary Link Web Part or a Summary Link field control.