Your customer wants to make sure all the conveyors and equipment are grounded to the same reference point. If you connect them all to the equipment grounding conductor (facility ground), you should be okay. You could test conveyor to conveyor & conveyor to machine by touching a conductive part (metal) of one conveyor or machine to a conductive part of a different conveyor or machine. You could go down the line testing each piece of equipment to its neighbor. If each measurement is less than the 10 ohms you should be compliant.