How to filter out duplicate items using MVVM

I'm trying to use one DataContext (ViewModel) to load my data once, and then use it in three different views.  I have it working for two of my views but the third one is my problem case.  Here's what I'm dealing with.

I have an ObservableCollection of Events, that contain EventDetails which contains a list of participants.

public class Events: ObservableCollection<EventDetails>
{
} 

public class EventDetails : ObservableCollection<Participants>
{
}

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The first two views are easy, the first view is just a list of Event->Name.  The second view is also pretty simple, it's the list of Events->Details->Participants in a TreeView.  The third view is much more difficult.  I want to display all of the Names of the Participants from all of the events but only showing 'unique' ones, no duplicates and put them in a ListView.

Is there a way to somehow use databinding while filtering out duplicate data?