How do I insert another line on a sales order if a certain line is entered?

I have a situation where when customers order a certain item, another item should be added automatically.  What is the best method to do this?

For example, if the item METER-A is entered on a sales order, I would like the system to automatically add another line with item CALIBRATION-A.  Is Advanced Pricing the best approach for this?

Thanks,

Mike