Using QR codes instead of VuMarks

My goal is to use qr codes instead of vumarks. I don't want to have to manually create hundreds of vumarks or image targets it needs to be scalable. I am using a 3rd party library (ZXing) to scan for qr codes and user defined targets. My solution works well for a single qr code but vuforia is unable to differentiate between different qr codes so problems arise when I want to scan and track multiple ones simultaneously. It seems the similarity threshold for image detection is too low as they are 5 star targets. If anyone has any suggestions it would be greatly appreciated. Thanks