Internal Interface implementation

Straight to the problem: I have a class that implements two interfaces:

public class A : Interface1, Interface2{
   // Interface 1 implementation...
   // Interface 2 implementation...
}

Is there a way (without creating another new class) to make Interface1 implementation internal and hide it from other components (only Interface2 will stay public)?

EDIT: Some more useful infos: Interface1 and Interface2 are defined as public in another core component and cannot be changed.

Thanks in advance,