Best Way To Span Multiple Columns in WPF Grid/List?

I have a custom user control I wrote in WPF to display some data. I want to show this usercontrol in a list, but I also want to provide multiple column headers (matching some properties on the user cotrol) so users can sort on properties contained in the usercontrol.

I am not sure the best way to go about this.

I currently have a ListBox displaying these user controls, but the ListBox has no header and I can't figure out how to put multiple headers on the ListBox.

Ideally I'd like something like this:

Header1   Header2  Header3   Header4
[UserControlThatSpansAllFourColumns]

My other thought was to use a DataGrid and somehow get each item to span multiple columns, but so far I can't figure that out either.

If anyone has any tips, I'd welcome them!