How can I connect 4 Display Monitors to my Macmini'13

Add one of these

http://www.matrox.com/graphics/en/products/gxm/dh2go/digital_me/

plus a USB video adopter like

http://www.tripplite.com/usb-3.0-superspeed-to-displayport-dual-monitor-external -video-graphics-card%20adapter-512-mb-sd…

or two USB adopters. Note the USB adopters tend to lag the installed video otput

Here is a USB>HDMI adopter

http://www.amazon.com/Cable-Matters%C2%AE-SuperSpeed-2048x1152-1920x1200/dp/B00B PEV1XK

Yes but note it has DVI output

Yes, a DVI>HDMI adopter will work. Make sure it is an DVI>HDMI and not HDMI>DVI

I have a question that is similar to the original. My church just got a mac mini that has 2 thunderbolts and 1 HDMI. Apparently only 2 ports can be used at any one time. We are needing wanting to have 3 distinctive displays while running Propresenter 6: a main monitor, front projector with all the graphics, and the back projector that either mirrors what we are displaying up front or something completely different. Is it possible to get 3 distinctive displays on a mac mini, or can it only be 2 displays and one would be mirrored for the 3rd?

I was looking at the DualHead and it looks like it only expands a display onto 2 instead of giving 2 distinctive displays.

One friend of mine was told by his Apple rep that on the Thunderbolt connectors he should be able to do 1 4k display on each or daisy chain 6 or 8 1080p monitors and get distinctive displays on each one. I am not sure what type of connector the rep was thinking that this can be done with, or if this is really even possible. Do you happen to know anything regarding this and whether it is possible or not?

Apple says the 2014 Mac Mini supports:

Support for up to two displays at 2560 by 1600 pixels, both at millions of colors

Thunderbolt digital video output

• Native Mini DisplayPort output
• DVI output using Mini DisplayPort to DVI Adapter (sold separately)
• VGA output using Mini DisplayPort to VGA Adapter (sold separately)
• Dual-link DVI output using Mini DisplayPort to Dual-Link DVI Adapter (sold separately)

HDMI video output

• Support for 1080p resolution at up to 60Hz
• Support for 3840-by-2160 resolution at 30Hz
• Support for 4096-by-2160 resolution at 24Hz

DVI output using HDMI to DVI Adapter (sold separately)

Not 2 4K screens but it may be able to do that if the two 4K screens are mirrored.

This

http://www.matrox.com/graphics/en/products/gxm/dh2go/digital_me/

for the dual-head says and shows the two displays are in extended desktop and not mirrored

I have looked at that adapter, but it only expands a single screen onto 2 screens. That is fine when doing graphic design or something, but when you are doing a presentation onto 2 projectors and want something different on each screen, that won't work. the best way to describe it would be like having a keynote presentation going. The computer screen itself will show you the previous, current, and next slides and the projector(s) have just the current slide going. With propresenter, you have the presentation software on the monitor, the current slide is on one projector and the other projector has the current and next slide displayed. So this cannot be a single display expanded onto 2 screens but needs to be separate monitor feeds.

If the two screens in Keynote can be moved then you can just move them to different screens