Two NEX units; one iPhone, AvicSync issues

[SoCal Bodybuilder]

Thank you to the admins for joining me here! I've been trying to find out what to do, and although I admit I have not thoroughly searched here yet, I am hoping there is a solution to my issue...  I have two vehicles; one with an AVIC-8100NEX, the other with an AVIC-8200NEX, and I have one iPhone 6plus, which I have tried to marry to both head units.  The problem is, that although I had already bought the live traffic map app for AvicSync on my phone, and married it successfully with the AVIC-8100NEX,  I was forced to re-buy it when I married it to the AVIC-8200NEX.  I don't mind the extra cost of the second purchase, IF it works.  Cutting to the chase, I have been unable to reunite the phone for the AvicSync with traffic map to both units, without having to "add new smartphone" each time I drive the other vehicle.  Major nuisance! I also had to download the bulky AvicSync map twice, which seems not right.  I hope there is a way to leave the phone united with both head units, and just get in, plug in, and go. Anyway, all input will be very much appreciated! Thank you, Charles M