How to check for matching properties using a JSON schema?

I'm making a Discord bot in Python that reacts to certain keywords in messages and my script uses a JSON file that might for example look like this:

{
    "characters": {
        "john": {
            "name": "Johnny",
            "hex_colour": "0xC61B1B"
            },
        "marc": {
            "name": "Marcus",
            "hex_colour": "0x8AC0FF"
            }
        },
    "reactions": [
        {
            "keywords": ["Hi", "Hello"],
            "quotes": {
                "john": ["Hello my name is Johnny"]
                "marc": [
                    "Hi there. I'm Marcus.",
                    "Not now, I'm looking for John, have you seen him?"
                ]
            }
        },
        {
            "keywords": ["Bye"],
            "quotes": {
                "john": ["See you later!"]
            }
        }
    ]
}

As you can see the structure is quite complex, so I decide to make a schema for it so vscode could point out any issues. It currently looks like this:

{
    "title": "Quotes data",
    "description": "Quotes bot data file",
    "type": "object",
    "properties": {
        "characters": {
            "title": "Character collection",
            "description": "A collection of the available characters.",
            "type": "object",
            "additionalProperties":{
                "title": "Character tag",
                "description": "A tag that represents the character as a short string",
                "type": "object",
                "properties": {
                    "name": {
                        "title": "Character name",
                        "description": "The name of the character.",
                        "type": "string"
                    },
                    "hex_colour": {
                        "title": "Character colour",
                        "description": "The hex code of the colour in 0x000000 format.",
                        "type": "string"
                    },
                    "image_url": {
                        "title": "Character image",
                        "description": "An url to an image of the character.",
                        "type": "string"
                    }
                },
                "required": ["name"],
                "additionalProperties": false
            }
        },
        "reactions": {
            "title": "Reaction collection",
            "description": "A list of the reactions",
            "type": "array",
            "items": {
                "type": "object",
                "properties": {
                    "keywords": {
                        "title": "Keyword list",
                        "description": "A list of keywords for the bot to react to.",
                        "type": "array",
                        "items": {
                            "title": "Keyword",
                            "type": "string",
                            "minItems": 1,
                            "uniqueItems": true
                        }
                    },
                    "quotes": {
                        "title": "Quotes collection",
                        "description": "A collection of characters with quotes.",
                        "type": "object",
                        "additionalProperties":{
                            "title":"Character tag",
                            "description": "A tag that matches a character above.",
                            "type": "array",
                            "items": {
                                "title": "Quote",
                                "description": "A quote to react with.",
                                "type": "string",
                                "minItems": 1,
                                "uniqueItems": true
                            }
                        }
                    }
                },
                "required": ["keywords", "quotes"],
                "additionalProperties": false
            }
        }
    },
  "required": ["characters", "reactions"],
  "additionalProperties": true,
  "allowTrailingCommas": true
}

So for the properties of the "characters" object, any property name is allowed, therefore I use "additionalProperties". Later on, for the "quotes" object, I did the same. But in this case, not any property should be allowed. Only those that match one of the properties of the "characters" object is allowed. Is there any way to make the schema check for matching properties?