Nope, no difference at all, whether it's just one or 3 devices connecting....
I'm planning a day at someone else's house and see if the problem persists over there.
same problem I had with my router and eMax, when it happens, have you verified that there is internet connection with other devices? It happened to me that if the Internet went away, even when it returned, the phone was not able to connect.
what i've thought that is an incompatibility of router with emax. For example i've two router (one for ground level) and seems i've this issue only with the router on the ground level :\
Have u tried to change wifi channel, band or encryption?