[Route("/service-a/", Verbs = "POST")]
public class DtoServiceA : IReturn<IList<string>>
{
}

public class ServiceA : ServiceBaseToSaveTyping
{
    public ServiceA(Funq.Container container) : base(container)
    {
    }

    public IList<string> Post(DtoServiceA request)
    {
        //do something that belongs to ServiceA
        //then resolve ServiceB and call Post() from ServiceB
        Container.Resolve<ServiceB>().Post(new DtoServiceB());

        return new List<string>();
    }
}

[Route("/service-b/", Verbs = "POST")]
public class DtoServiceB : IReturn<IList<string>>
{
}

public class ServiceB : ServiceBaseToSaveTyping
{
    public ServiceB(Funq.Container container) : base(container)
    {
    }

    public IList<string> Post(DtoServiceB request)
    {
        //do something that belongs to ServiceB
        return new List<string>();
    }
}

public IList<string> Post(DtoServiceA request)
    {
        //suppose if I control db connection like so
        using (var conn = IDbConnectionFactory.Open())
        {
            //do something that belongs to ServiceA
            //then resolve ServiceB and call Post() from ServiceB
            Container.Resolve<ServiceB>().Post(new DtoServiceB());
            //above line will fail because connection has already been opend by ServiecA.Post()
        }
    }

    public IList<string> Post(DtoServiceB request)
    {
        //suppose if I control db connection like so
        using (var conn = IDbConnectionFactory.Open())
        {

        }
    }

public IList<string> Post(DtoServiceA request)
    {
        //suppose if I control db connection like so
        using (var conn = IDbConnectionFactory.Open())
        {
            //move code to a searapte "none servicestack service", which
            //can be just a normal c# class
            Resolve<NoneServiceStackServiceA>().DoSomething();
            Resolve<NoneServiceStackServiceB>().DoSomething();
        }
    }

    public IList<string> Post(DtoServiceB request)
    {
        //suppose if I control db connection like so
        using (var conn = IDbConnectionFactory.Open())
        {
            //move code to a searapte "none servicestack service", which
            //can be just a normal c# class
            Resolve<NoneServiceStackServiceB>().DoSomething();
        }
    }