I'm playing on a SMP server and am trying to use the Nether to link up all my disparate bases around the world. Note in the below, A is Overworld, B is Nether.
I started with one portal (A1, thus spawning B1 in the Nether), and then created another portal a ways away in the Nether (B2), hoping it would be near the main area all the other players congregate. It (A2) was pretty close to where I wanted it, but not exactly. I then created another portal a short distance away (A3), which was where I was hoping A2 would land. I then went somewhere in the neighborhood of 400 squares away from where I initially built A1 (in the opposite direction of A2/A3) and created another portal, A4.
One would think A3 and A4 would create B3 and B4 on the Nether side, respectively. However, A4 linked to B1, and A3 linked to B2. The weird part is, A1 is further from A4 than A1 is from A3.
I hope that made any sense. My question is:
How far away do portals on the Overworld map need to be from each other in order to spawn separate portals in the Nether? Or, what are some ways to ensure a new portal won't link to an existing one?