Dual ethnicity reporting

Hello

I know this topic has been discussed from a reporting perspective and there are BIP solutions on here. However, my question is how you are reporting to US authorities when someone has more than one ethnicity?

Whilst you can "fudge" the reporting (and my reports are OTBI so I would have to do something here rather than via a DM), is this correct to do this?

There is the primary flag which would only return one record of course, but how do US members report to external bodies on this when a member selects more than one? If you don't include the primary flag you would get a duplicate record for the 2nd ethnicity.