QUESTION: Apply observable on object rather than creating object inside observable

so I've tried to comprehend ReactiveX as a library for some time now and I believe I'm starting to get the hang of the fundamentals, however, there is one problem I have which I can't find a solution to in the docs...

tldr: I want to either connect an observable to a class without actually creating the class inside the observable lambda or, create the class inside the observable but then be able to extract the class. In the end all I want to to is in some way or form make an observable of a class and then be able to use the class outside the scope of the observable.

Situation: I have three layers of classes, I have class A, B, and C, where A holds in all Bs and later all Bs, holds in multiple Cs. Both classes B and C may exist in multiple instances (A is always only one instance).

Problem: So in my application, class A will create an instance of C, and make it observable using Rx. When C is instantiated and ready I want to take the class and pass it to one of the B instances. However, my problem is that since I need to create the C class in a lambda in the observable create method I can't actually do anything with the new C Class, it only exists in the lambda scope. So what I want to do is either pass in a reference of C to the observable and give it the subscriber or somehow return the C instance out from the observable lambda. I tried giving the lambda a pointer to my class and make the lambda mutable but when doing that rx gave me compile errors and complained about the Rx method being const.

const auto test = rx::observable<>::create<something>([&](rx::subscriber<something> subscriber) {
    C c(subscriber);
});
// Here I want to access c

I tried passing it in like this but with no success

class C {
   C(rx::subscriber<someting> subscriber) {
       subscriber.on_next(55);
   }
};

C* c = nullptr;
const auto test = rx::observable<>::create<something>([cLambda = c](rx::subscriber<something> subscriber) mutable {
    cLambda = new C(subscriber);
});

test.subscribe([](something input) {
    std::cout << "Called " << input<< std::endl;
});
// Compile error: C3848: expression having type 'const main::<lambda_d3f00...>' would lose some const-volatile qualifiers in order to call 'void main::<lambda_d3f00...>::operator ()(rxcpp::subscriber<something,rxcpp::observer<T,void,void,void,void>>)'
// with
// [
//     T=container
// ]

Do any other methods exist to accomplish what I want or have I misunderstood the concept of something here?

ReactiveX / RxCpp

QUESTION: Apply observable on object rather than creating object inside observable #518