Create And Share Resource Pool. Open the sharer or project that will share resources from the pool. Create a resource pool Resource pools can be created using XenCenter or the CLI.

If there is foo is returned from pool if not foo is created from XML and saved to pool. Create a classification function to identify external script requests. In the On conflict with calendar or resource information select Pool takes precedence then.
To create a resource pool you simply set up a project file that contains only resource.
Create a new blank project and name the file in such a way that everyone will know it is a resource pool file and not a project file. Under the resources tab you should see the option for Resource Pool. I was thinking about something like resource pooling where program asks pool if there is Entity with name foo in pool. Use the resource pool.