Have you read the link that I provided in my last response? If not, I would start by doing that. Without the information on that page you are really shorthanding yourself.
To do this, you must commit to giving them a shot together. Once you are ready, prepare a new area to introduce all of your pigs you want living together in. This should be an area that none of the pigs are familiar with, and with none of their smells around. Follow the instructions in the link on how to introduce the pigs, what behavior is normal, and what behavior is not. If introductions are done as suggested in the link and there is no blood drawn, place them in the cage (which needs to be completely cleaned, top to bottom, with no accessories either pig has had in the cage unless it, too, has been cleaned). Familiarize yourself with what behavior to expect, and be confident in your pigs. My last intros were full of (at times very scary) aggression, but now all is well. Best of luck, and let us know if you have more questions.