I just ran a test just like yours. And in fact I was not able to see both outputs at the same time. I don't think it has anything to do with the UUID, but with SPP-loopback.py itself. I think it is the example itself that only receives the first connection available. So my suggestion is that if you want to achieve that behavior, you will have to study the example's source. Then you will have to modify it and get it to catch a second connection in another port. This may prove challenging but it sounds like a cool project to work on.
I actually tried running the SPP-loopback twice in the background but varying the UUID in each time and it worked. I was actually able to communicate with two smartphones to one edison at the same time. This can be done as follows:
root@oldedison:~# python SPP-loopback.py "1101" &
root@oldedison:~# python SPP-loopback.py "1105" &
Do not forget to change the UUID in the mobile phones as well.