How to access methods of an object through an interface?

Question

Design patterns

Example: there are 2 isolated objects A and B, inherited from the interface, it is necessary that the object A has access to the methods of B through a single method of the interface. How to implement this because the objects do not know anything about each other's methods. Template virtual functions come to mind, but it's impossible to put everything together. I ask without criticism, I only delve into the patterns. Thank you.

Answer 1

Try to make one common parent class through which communication between methods takes place