menu-data.json

{
    "main": "food",
    "sub": "bread"
}

menu-schema.json

{
    "type": "object",
    "required": ["main", "sub"],
    "oneOf": [
        {
            "title": "Food menu",
            "properties": {
                "main": {"enum": ["food"]},
                "sub": {"enum": ["bread","steak"]}
            }
        },
        {
            "title": "Drink menu",
            "properties": {
                "main": {"enum": ["drinks"]},
                "sub": {"enum": ["water","juice"]}
            }
        }
    ]
}