How to set up 4 monitors using XFX Black Edition Double D Radeon R9?

Hi, can anyone help me here. My card has 2 dvi , 1 hdmi and 2 mini diplay port
I’m currently using triple monitor ( hdmi, mini display port and dvi ) when I tried to connect 4 monitor to another dvi slot, it wont let me.. I assumed I need to get another active mini display port adaptor but I’m worry it may not work too. will it work using another display port?
Do I need to get another another card for the 4th monitor?
this is no gaming nor eyefinity. Just want to get use 4 monitors for work.
Answer #1
As far as I know, you have to use as many Display Ports as you can. DVI can only take one and one HDMI.
Answer #2
You have to use the display port for this; AMD support a lot of monitors but you need the display port, or an external video card(you can find them for cheap and you only need to connect them to usb).