How to assign the supplier sites to multiple operating unit ? I have about 24000 sites which needs t

I have did initial conversion of supplier sites and trying to figure out the best way to assign these imported sites to 10 different operating units?

When I tried to insert one existing supplier site to interface table with different operating unit id, the import failed and shown "Address/PartySite name already exists for the Supplier. Please re-enter a unique one."