You can only use a 6x8 multiswitch to get more than 4 outputs out of a triple sat dish.
You will need to take the 4 outs from the triple LNB and run them into the mutiswitch and use the first 4 inputs 13v and 18v , dont use the expansion ports.
And now you will have 8 out puts to feed all your needs of your home, always use RG6 and home runs from the 6x8 switch.
You CAN NOT use a 3x4 with a triple sat dish, as you found out .
The triple sat LNB has switching built in to it, that is why you can hook 4 recievers to it DIRECT.
The 3x4 was mainly used to get 4 out puts from a dual output SINGLE LNB. at which you would run dual cable to the 3x4 switch and get 4 outputs, all we did above is now you have 4 out puts and need to go to a switch that would take the 4 feeds into the switch and make it 8 output.
Hope this helps...