Two observal collection to remove an item

Question

I have a two view model, if i want to delete a item in one model it may affect another model but both having same id..

 

Using two observal collection i want to remove item with same id's.

 

Note: C# Code 

private void WindowSize_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)

{

if (e.Action == NotifyCollectionChangedAction.Add)

{

if (WindowSize[e.NewStartingIndex].WindowSizeId == 0)

WindowSize[e.NewStartingIndex].WindowSizeId = WindowSize.Max(x => x.WindowSizeId) + 1;

WindowSize[e.NewStartingIndex].PropertyChanged += WindowSettingProjectViewModel_PropertyChanged;

}

else if(e.Action==NotifyCollectionChangedAction.Remove)

{

////HERE i want to write a code by matching two collection to  with same ID 

}

}