Back with G4 (and maybe early G5?) you could have all the receivers you wanted because the Dexcom RF transmitter just sent out the signal and any receiver with the code could pick it up. The brains were in the receiver devices so my Animas pump sometimes showed different numbers than my Dexcom receiver. I can also remember using two Dexcom receivers simultaneously but I can’t remember why. The initial Dexcom phone app got its info from the Dexcom receiver not the transmitter.
That is not true with G6.
Because of the necessity to pair with the G6 transmitter using Bluetooth, you can no longer have multiple receivers or smart devices. Technically one receiver (pump) medical device communicates with one Bluetooth channel and one smartphone device pairs with the other Bluetooth channel. The Bluetooth channels are different so you can’t have two phones connecting with the transmitter or two pumps.
I think most people know that SugarMate works through Dexcom Share and does not get its information directly from the transmitter. Thus you can have both the G6 app and Sugarmate on your phone.
Someone with xdrip can correct me, but I think xdrip pairs with the transmitter Bluetooth and therefore you can’t have both the G6 app and xdrip working on your phone at the same time.