@Mapper(config = FooBarConfig.class)
public interface FooBarMapper {

    Bar toBar(Foo foo);

    Foo toFoo(Bar bar);

}
@Data
class Foo { int secret; }
@Data
class Bar { int secret; }

@MapperConfig(mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_ALL_FROM_CONFIG)
interface FooBarConfig {

    @Mapping(target = "secret", ignore = true)
    Bar toBar(Foo foo);

    @InheritInverseConfiguration(name = "toBar")
    Foo toFoo(Bar bar);
}

public class FooBarMapperImpl implements FooBarMapper {

    @Override
    public Bar toBar(Foo foo) {
        if ( foo == null ) {
            return null;
        }

        Bar bar = new Bar();

        return bar;
    }

    @Override
    public Foo toFoo(Bar bar) {
        if ( bar == null ) {
            return null;
        }

        Foo foo = new Foo();

        foo.setSecret( bar.getSecret() );

        return foo;
    }
}

@MapperConfig(mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_FROM_CONFIG)
interface FooBarConfig {
    @Mapping(target = "secret", ignore = true)
    Bar toBar(Foo foo);
    @Mapping(target = "secret", ignore = true)
    Foo toFoo(Bar bar);
}