How it can be possible create sub-document with multi schema validation ?

[Sina]

hello , 

I want to implement a validation on sub-document with two or more specific types , 

It should support validations

It is better support updating subdocs with doc functions too

I don't know what is the best implementation for adding this feature , with plugins , custom validations ,custom types or ...

var typeOne = new Schema({
    info:String,
    message:String
})

var typeTwo = new Schema({
    url:String,
    names:[String]
})

var itemSchema = new Schema({
    authorId : { type:ObjectId, required:true, ref : 'user' },
    authorType : { type:String, required:true, enum:userTypes },
    detail :  {},//no any validation here
    itemType : {type:String,required:true,enum:itemTypes}
})
var itemSchema = new Schema({
    authorId : { type:ObjectId, required:true, ref : 'user' },
    authorType : { type:String, required:true, enum:userTypes },
    detail :  {type:[typeOne,typeTwo]},//I prefere it can be like this
    itemType : {type:String,required:true,enum:itemTypes}
})