Multiple Monitors: 3 Surround Plus 1?

Hi, I'm racking my brain on this one, and need help, or my grand plan goes in the toilet.

Running FSX. My system is:

MSI Z170A Krait Gaming 3X Motherboard

MSI GeForce GTX-950 2GB (GPU #1)

MSI GeForce 710 (GPU #2)

I have 5 displays. There are 3 24" displays for my main viewscreen, a 15" screen for my instruments, and a 5" screen for my GPS.

Initially I Had the 3 main displays on the 950 and the 2 other displays on the 710. The issue is the FSX apparently doesn't play nice with more than one GPU: When I undock the GPS and drag it to the 5" display, DirectX11 goes haywire, GPS goes black, the mouse starts flickering rapidly between an arrow and a spinning wheel, and FSX crashes and restarts.

So, I tried to move everything to the 950, which technically can only handle 4 monitors. I thought using a 3-hub display port hub would trick the GPU into thinking that the 3 main displays are only one display. Clever. It didn't fall for it one bit. It only recognized 4 of the 5 displays.

Then I tried keeping the 15" display on the 710 GPU by itself (I'm using Air Manager on it for my instruments, so my theory is that FSX won't actually be involved with a 2nd GPU). The problem is that I can't get the 3 main displays to go into surround mode while the 4th 5" display (VGA) plugged in.

How do I solve my problem (cheaply) and get a setup that works for my needs?

thanks, Dave