Nether portals linked to one portal?

[N1ghtmareD0GE]

This is kinda hard to explain but I'll try my best.

In a vanilla Minecraft single-player world, you can make a Nether portal to go to the nether, lets say I go 1000 blocks away from that portal I made in the over-world and make a new portal, I go inside and new Nether chunks load and I'm in a completely different area in the Nether, far different from the first portal. This is useful since I'm playing in survival and want to travel from place to place fast. 

Now the problem is on my server, all the Nether portals I make, even if I did it thousands upon thousands blocks away from the first portal I created, will teleport me to the first portal I made. No new generated Nether chunks and I can't travel from place to place. All Nether portals lead up to the area I already loaded (In the Nether) and if I created a new portal in the Nether it will teleport me to the portal which has already been made in the overworld.

 

Is there any fix to this? Thanks.

This guy explains what I'm trying to do: