Best Pratices Domain Entities Composition?

I have the following project structure:

- Application.DataAccess      : IUserRepository....
- Application.DataAccess      : IUserRepository....
- Application.Busines         : IUserService, ICustomerService...
- Application.Infrastructure  : Logging, Exception handling... (Cross-cutting.)
- Application.Domain          : User, Customer... (Entities)
- Application.WindowsForms    : UI

Almost all of my service operations will have the following parameters:

• User userOfOperation (That is in Doimain layer and represents a user)


• PlaceOfOperation placeOfOperation (That is in Doimain layer and represents a branch office)

I think that i should create a new class and encapsulate this entities on it then call it"OperationSource".

like:

class OperationSource 
{
   Domain.User UserOfOperation { get; set; }
   Domain.Enterprise PlaceOfOperation { get; set; }
}

Where should i put the compose classes (e.g OperationSource) in this case, on my Application.Busines or Application.Domain?