Model - ViewModel sync and filtered ObservableCollections - wpf

Question

I am working with EF and MVVM.
My Model contains this:
Public Property Visits As DbSet(Of Visit)
The Visit class implements INotifyPropertyChanged and its properties properly raise PropertyChanged events.
My ViewModel contains these properties, used for my views binding (context is my model):
Private _BareVisits As ObservableCollection(Of Visit)
Public Property BareVisits As ObservableCollection(Of Visit)
Get
If _BareVisits Is Nothing Then
_BareVisits = New ObservableCollection(Of Visit)(context.Visits)
AddHandler _BareVisits.CollectionChanged, AddressOf BareVisits_CollectionChanged
End If
Return _BareVisits
End Get
Set(value As ObservableCollection(Of Visit))
_BareVisits = value
End Set
End Property
Private _Visits As ObservableCollection(Of Visit)
Public Property Visits As ObservableCollection(Of Visit)
Get
If _Visits Is Nothing Then
_Visits = New ObservableCollection(Of Visit)(
BareVisits.Where(
Function(V) Not V.IsMediGenerated AndAlso V.IsHistoryParseComplete
)
)
End If
Return _Visits
End Get
Set(value As ObservableCollection(Of Visit))
_Visits = value
End Set
End Property
Private Sub BareVisits_CollectionChanged(sender As Object, e As NotifyCollectionChangedEventArgs)
Select Case e.Action
Case NotifyCollectionChangedAction.Add
context.Visits.AddRange(e.NewItems.OfType(Of Visit))
context.SaveChanges()
Case NotifyCollectionChangedAction.Remove
context.Visits.RemoveRange(e.OldItems.OfType(Of Visit))
context.SaveChanges()
Case Else
Exit Sub
End Select
End Sub
As you see, the BareVisits property is just the DB collection of my Visits.
The Visits property (the one my view is bound to) depends on BareVisits to return filtered records.
Questions:
1) Which is the best method to save a new visit? By using the event handler posted? Or should I talk to the Model directly and somehow bubble this changes to the ViewModel? If I hook the CollectionChanged handler to the Visits property, do I need this BareVisits property at all?
2) Suppose the changes take place in the Model itself, I suppose I should also perform the record adds / delete to the BareVisits property also. What happens to the Visits property? (the filtered one) I have tried everything and its CollectionChanged event is never fired. Should I tamper with it also by hand?
I just want my view to depict the data changes and I am at a loss.
EDIT: I have also tried to use ICollectionView to filter the raw data (instead of a new ObservableCollection property) but it is not a choice since the data in my datagrid is rendered un-editable this way.
Thank you in advance. Any help will be greatly appreciated.