Any way to tell if an object is inside another class?

[Ruby The Roobster]

For example:

class test {}
class T {
auto c = new test();
}

Any way to tell if an object of type test is a member of object 
T? I don't want to use the name of the member variable. I just 
want to know if this works in general.
Why am I asking this? Because I need it to develop this Multiple 
Alias This project I am working on(basically just mashing all the 
functions into a class and then using the class with alias this)