I can not speak for a full interpretation of QS9000. However, I understand that one approved method is through the 2pCP (which means 2nd Party Calibration Program). The way this works is that you send an auditor to be trained to audit within this program. Once your auditor has been trained and approved, you can then audit your non-accredited calibration subcontractors. The caution is that they are quite strict regarding minimum experience and training the auditor must already have prior to attending this class.
I am familiar with this because I am supposed to go to this class this year. Further, it is offered only in Michigan. So your already experienced auditor must attend the class there. You can check with AIAG to see if it is offered at international locations. Since I am not an expert on this, I suggest you contact AIAG for more information.