We can use explicit mapping:
// As precise IService1 mapping as possible
x.For<IService1>()
.Use<x.services.service1.Service1>()
.Ctor<IValidator>("validator")
.Is<x.services.service1.Validator>();
// IService2
x.For<IService2>()
.Use<x.services.service2.Service2>()
.Ctor<IValidator>("validator")
.Is<x.services.service2.Validator>();
EDIT: to make some type singleton
x.For<x.services.service2.Validator>()
.Singleton()
.Use<x.services.service2.Validator>();