3-Monitor + HDMI Hud Dash

I just recently put together a new racing sim rig (custom DIY) I have 3 monitors running off a GTX 970 via the three display ports.  The game I'm running is Project Cars 2.  I'd like to add a Hud Dash using a small 5" monitor (used for video production) via the HDMI cable from the same GTX card.

I've successfully set up the 5" and got it to show the dash when I was racing with one monitor.  Separately I was able to get all three monitors to work with PC2.  However, I am unable to get both to work together.  PC2 doesn't seem to recognize the 3 monitor setup when I effectively have 4 monitors running.

Is it possible to get this to work?

BTW, I have two GTX970s in the case if that makes a difference.