In our training we tried to use 4 spot targets in parallel. But RyngDyng only recognized 2 of them. The post Targets not recognized did not help either.
Maybe you are using a RyngDyng type RD600? Observing 4 targets simultaneously is supported by default only with type RD720.
In case you are interested in upgrading your RD600 to manage 4 targets just get in contact with Archery Analytcs.