Quote fromQuote fromNot all your portals connect to your first one - just explore a bit more with them. Portals get created on the nearest dry ground within a certain distance of the proper origin, on both the Nether and main world sides.
Really, it doesn't look that way. As I said, I've created the first portal in my 'base', and the second one very far away from it. For the first one, a portal appeared in the Nether, but not for the second one. For some reason, the second one led to the same portal as the first one. Seems like no new portal was created in the Nether.
Just make a god damned portal in the nether yourself. It'll link to the closest portal in the nether so just make and activate one.