When building the NodeDefinitions model, it is possible to make a NodeDefinition with an isln relation with several NodeDefinitions including those already with isln relation. All that is needed is to link the NodeDefinitions with isln relations. Note that a NodeDefinition must always have an isln relation with a NodeDefinition on a lower level.
In the example below, the NodeDefinition Cabinet has an isln relation with the NodeDefinitions Wiring Room and Floor which themselves have an isln relation. Cabinets can be created in wiring rooms and floors, and wiring rooms in floors.
