I've attached a sample VS2008 WPF project that illustrates one approach to this scenario. In the sample, I created a test data collection. I added a string property called header and made sure that the test data had items with duplicate Header names. I then added a ViewModel and in the ViewModel, I create a collection of collections grouped by Header name. I bound the collection of grouped items to the XamTabControl. Each tab control contains a XamTilesControl which displays each group of items.

Let me know if this helps.

Thanks