Need help grouping annotated classes in Android Kotlin project

I'm currently working on a project where I need to group classes annotated with the @MainType and @SubType annotations. The @MainType annotation is applied to the superclass, while the @SubType annotation is applied to the subclasses.

I'm trying to achieve this using Kotlin reflection, but I haven't been successful so far.

Here's an example of what I'm trying to achieve:

@MainType
open class Animal {
    // ...
}

@SubType("dog")
class Dog : Animal() {
    // ...
}

@SubType("cat")
class Cat : Animal() {
    // ...
}

I want to group the Dog and Cat classes under the Animal class, like so:

val typeTable = hashMapOf(
    "Animal" to hashMapOf(
        "dog" to Dog::class,
        "cat" to Cat::class
    )
)

I want to achieve this using reflection.

I'm not very familiar with using reflection in Kotlin, but I've tried playing around with it to achieve my goal. Still no success