I came across a survivor in the south bunker on the first resort map. I think his name is Jose. I can't seem to get him to talk to me once I kill the zombies outside the fence that are trying to get him. Basically I have no idea how to save him or get to the 'portal'.
This sounds like Jose Garcia. You'll have to kill 2 Thugs and 4 Walkers that are right outside the fence before he'll talk to you.
Some people have reported that occasionally one or more of the zombies might glitch and end up inside the fence where you can't kill them. If you haven't killed 6 zombies, look around a bit, and then try saving and resetting the game to see if that fixes it.