What would be proper structure of RequestValidation plugin usage

Question

In documentation and code samples of Ktor, regarding RequestValidation plugin (https://ktor.io/docs/request-validation.html) there are validators for different types but all defined on same place, within install(RequestValidation) {}

install(RequestValidation) {
    validate<String> { bodyText ->
        if (!bodyText.startsWith("Hello"))
            ValidationResult.Invalid("Body text should start with 'Hello'")
        else ValidationResult.Valid
    }
    validate<Customer> { customer ->
        if (customer.id <= 0)
            ValidationResult.Invalid("A customer ID should be greater than 0")
        else ValidationResult.Valid
    }
    validate {
        filter { body ->
            body is ByteArray
        }
        validation { body ->
            check(body is ByteArray)
            val intValue = String(body).toInt()
            if (intValue <= 0)
                ValidationResult.Invalid("A value should be greater than 0")
            else ValidationResult.Valid
        }
    }
}

Is there a better approach to this? This would not make any sense if we are to validate lots of different request body types. Is there a way to structure these "validators" in separate files/classes and register only once at install(RequestValidation) {} or something similar?

EDIT: Only other approach I could think of is this:

RequestValidation.kt

fun Application.configureRequestValidation() {
    install(RequestValidation) {
        validate<RequestBodyType> {
            requestBodyTypeValidation(it)
        }
    }
}

SomeFeatureRouting.kt

fun requestBodyTypeValidation(requestBody: RequestBodyType): ValidationResult {
    // Validate requestBody properties here
}

Marginally cleaner but kinda to coupled