Hello @guyt, thank you for bringing this up. At the moment, custom mapping can be done, and then subsequently map the SNOMED, though this may take several months. We can check the SNOMED during SNOMED refresh.
If this can be of help, we have one concept for Islanders that you may use: Athena
Similar issues have also been discussed in the forum, and this link may help shed some light into your concern as well: Race and Ethnicity in the OMOP CDM