I have seen video of multiple phantom's flying from NAB, and some other stuff on YouTube, so I would assume it is possible.
Having said that though.....
DJI won't let you use any other 2.4GHZ device - like the GoPro WiFi at the same time because of interference.
Would I do it? Most likely not.
Be careful. Be prepared to have both of you turn your radio's off in the event of erratic flying to turn on the Return to Home feature.
Hope this helps
D