RadListView provides the option to set its group headers as sticky. This means the GroupHeader will "freeze" while scrolling through the items until the whole group is scrolled away. As you scroll through the next group, the currently sticked group header will be pushed by the next group header.
To enable the sticky group headers behavior, just set IsGroupHeaderSticky property of the ListView to True. By default IsGroupHeaderSticky value is False.
<telerikDataControls:RadListView x:Name="listView" IsGroupHeaderSticky="True" />
var listView = new RadListView(); listView.IsGroupHeaderSticky = true;
Check below the sticky group headers in action: