I'm somewhat unclear as to what you're asking.
Assuming that last pair is being connected to to the same two amp channels, their combined rated impedance is around 3.4+ ohms.
If your receiver is rated to four ohms andand neither speaker dips too far below their rated impedance (many do) then you should be somewhat safe at low to moderate levels. No guarantees at high levels, though. Actually, no guarantees either way.
Oh, wait... do you mean hooking all three pairs of speakers up to the same two amp channels? If so, that's playing with fire.
Now, if each speaker is connected to their own channel. you should be fine.