How to Hide Base Rate if an OVERRIDE RATE exists for the lane?

If an OVERRIDE rate exists for a lane, we want that to be the only valid rate - the base rate should (at very least) be invalid or (ideally) completely hidden and unavailable.

In looking at the table definition for RATE_GEO, I see a field named IS_MASTER_OVERRIDES_BASE

Can someone please enlighten me on what this field is used for, and if it can be used to accomplish what we want?

Thanks in Advance.