How to use the PocoDynamo.GetRelatedItems method

I am using PocoDynamo to store UsersInOrganization. I have the following class:

using System;
using ServiceStack.DataAnnotations;
using SimOpSolutions.Domain.ExtendedModels;

namespace SimOpSolutions.Domain
	public class UserInOrganization : BaseModel
        public long Id { get; set; }

        public Guid UserId { get; set; }

        public long OrganizationId { get; set; }
        public long RoleId { get; set; } //User Can Only be One Role within an Organization

Then I am creating a query like this:

var usersInOrganizations = Db.FromQuery<UserInOrganization>(x => x.UserId == message.UserId).Select<UserInOrganization>().Exec();
var relatedItemsTest = Db.GetRelatedItems<UserInOrganization>(message.UserId);

But both items are return the same thing. What should I expect to be returned from the GetRelatedItems method?

GetRelatedItems is just a simple wrapper around fetching related items, you can view the source code to see its implementation for what request it sends.