How do you describe a resource being contained in a spatial element?

Originally here: https://forums.buildingsmart.org/t/how-do-you-describe-a-resource-being-contained-in-a-spatial-element/3587

If I have an `IfcConstructionResource`, say for spare parts, how do I say that these parts are stored in Room XYZ?

The closest relationship I can find is documented below (emphasis mine):

> A resource may be assigned to a product by [IfcRelAssignsToProduct](http://localhost:8001/schema/ifckernel/lexical/ifcrelassignstoproduct.htm) where *RelatingProduct* refers to an [IfcProduct](http://localhost:8001/schema/ifckernel/lexical/ifcproduct.htm) and *RelatedObjects* refers to one or more IfcConstructionResource or other objects. Most commonly an [IfcElement](http://localhost:8001/schema/ifcproductextension/lexical/ifcelement.htm) subtype is assigned indicating the product to be constructed, **where such product is connected to a spatial structure** which in turn is aggregated within the [IfcProject](http://localhost:8001/schema/ifckernel/lexical/ifcproject.htm).

Is there an undocumented assumption here that using IfcRelAssignsToProdut where the RelatingProduct is an IfcSpatialElement is equivalent to a "contained in" relationship?

Is there are more elegant solution?