I recant.
Pigsonthewing was correct in his initial review. NCI Thesaurus ID is better to be treated as a pure Code string to be used across multiple Value Sets that NCI maintains mappings for https://ncit.nci.nih.gov/ncitbrowser/ajax?action=create_src_vs_tree&nav_type=valuesets&mode=0 . In other words, the NCI Thesaurus ID Code string can be queried across multiple NCI URLs (sub databases) not only the NCIt database.
And it looks like we already created a property to hold the CUI Concept Unique Identifier https://www.wikidata.org/wiki/Property:P2892 that NCImetathesaurus (NCIm) uses as the top level identifier in its grand terminology database which holds complete mappings. https://ncim.nci.nih.gov/ncimbrowser/pages/concept_details.jsf?dictionary=NCI%20Metathesaurus&code=C0007465&type=all
So, in short, we are in excellent shape for cross references.