I have a selection field as follows:
    source = fields.Selection([
        ('one', 'First'),
        ('two', 'Second'),
        ('three', 'Third'),
        ('four', 'Fourth'),
        ('five', 'Fifth'),
    ], required=True, default='one')
How can I show but inactive some of these options?
at the moment these options are all visible and selectable but I want some to be visible but inactive so not being selectable.
