public static void CreateSelectionFilter(Document doc, View view)
{
    // find room tags in this view
    FilteredElementCollector collector = new FilteredElementCollector(doc, view.Id);
    collector.WherePasses(new RoomTagFilter());

    // collect tags whose room number matches criteria
    List<ElementId> tagIds = new List<ElementId>();

    foreach (RoomTag tag in collector.Cast<RoomTag>())
    {
        int number = Int32.Parse(tag.Room.Number);
        if (number % 3 == 0)
        {
            tagIds.Add(tag.Id);
        }
    }

    using (Transaction t = new Transaction(doc, "Create SelectionFilterElement"))
    {
        t.Start();

        // Create selection filter and assign ids
        SelectionFilterElement filterElement = SelectionFilterElement.Create(doc, "Room tags filter");
        filterElement.SetElementIds(tagIds);

        ElementId filterId = filterElement.Id;

        // Add the filter to the view
        view.AddFilter(filterId);

        doc.Regenerate();

        // Use the existing graphics settings, and change the color to Blue
        OverrideGraphicSettings overrideSettings = view.GetFilterOverrides(filterId);

        overrideSettings.SetProjectionLineColor(new Color(0x00, 0x00, 0xFF));

        view.SetFilterOverrides(filterId, overrideSettings);

        t.Commit();
    }
}

Public Shared Sub CreateSelectionFilter(doc As Document, view As View)
    ' find room tags in this view
    Dim collector As New FilteredElementCollector(doc, view.Id)
    collector.WherePasses(New RoomTagFilter())

    ' collect tags whose room number matches criteria
    Dim tagIds As New List(Of ElementId)()

    For Each tag As RoomTag In collector.Cast(Of RoomTag)()
        Dim number As Integer = Int32.Parse(tag.Room.Number)
        If number Mod 3 = 0 Then
            tagIds.Add(tag.Id)
        End If
    Next

    Using t As New Transaction(doc, "Create SelectionFilterElement")
        t.Start()

        ' Create selection filter and assign ids
        Dim filterElement As SelectionFilterElement = SelectionFilterElement.Create(doc, "Room tags filter")
        filterElement.SetElementIds(tagIds)

        Dim filterId As ElementId = filterElement.Id

        ' Add the filter to the view
        view.AddFilter(filterId)

        doc.Regenerate()

        ' Use the existing graphics settings, and change the color to Blue
        Dim overrideSettings As OverrideGraphicSettings = view.GetFilterOverrides(filterId)

        overrideSettings.SetProjectionLineColor(New Color(&H0, &H0, &Hff))

        view.SetFilterOverrides(filterId, overrideSettings)

        t.Commit()
    End Using
End Sub