If there are balances cannot be reconciled properly, while the difference are not material / not significant to the Financial Statement. The balance can be 'dumped' into trade receivable/ trade payable a/c balance. This is because, amount due from / amount due to inter-company should be nil at Group level Financial Statement.
Un-reconciled inter-company balance can result in inter-company balance not fully eliminated. In practice, the un-reconciled would be written off or classified as trade receivable/ payable (while the difference is not material) to the Group account.