1. A computer implemented method of amending an object oriented model comprising the steps of: adding a registry listener to each object of the group of objects in the object oriented model, wherein each respective object inherits support for adding the registry listener and for notifying the registry listener about changes to relationships between the respective object and other objects of the group of objects; responsive to the registry listener receiving a notification of changes to a relationship between the object and other objects in a group of objects, updating a registry to reflect changes to the relationship between the object and the other object group objects, wherein the registry comprises a referencing object and a referenced object for the object, and wherein updating the registry comprises steps of: identifying a first object to be added to the group of objects in the object oriented model; identifying a second object of the group of objects to be replaced by the first object; the computer using the registry to retrieve a first set of one or more relationships between the second object and other object of the group of objects; and the computer using the first set of one or more relationships to configure the first object of the group of objects in the object oriented model so as to assume a second set of one or more relationships corresponding to the first set of one or more relationships with the other objects of the group of objects.