When using optgroup hierarchy, can the parent be searched/filtered?

[robsilva]

Given a hierarchy as such:

options = [
        {
            label: 'Earth',
            options: [
                { value: 'luna', label: 'Moon' },
            ],
        },
        {
            label: 'Mars',
            options: [
                { value: 'phobos', label: 'Phobos' },
                { value: 'deimos', label: 'Deimos' },
            ],
        },
        {
            label: 'Jupiter',
            options: [
                { value: 'io', label: 'Io' },
                { value: 'europa', label: 'Europa' },
                { value: 'ganymede', label: 'Ganymede' },
                { value: 'callisto', label: 'Callisto' },
            ],
        },
    ];

I would love to be able to filter by 'Earth' and have its children appear. Is that possible? If so, how might one go about achieving that?