Check with your data processing vendor to see if they can help you segregate and monitor these loans as a group more or less as Cape Codder describes. Treat your auditors' request as a wish list, not as a "requirement" you have to satisfy.
If your vendor can supply you with some standard reporting with this information, then make that your counteroffer. Do not invent the wheel.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.