Each door has a pair. and can only teleport you to the other pair.
So four doors at my base and their corresponding pairs at the poles?
I like it. I would use that. What happens if you bring one half of a pair to another world? Can you register a new door to be a replacement?
Is that in the op?
If I’m reading this right, you can make 4 different pairs of portal objects. Each pair allows teleporting between them.
I like it. It’s easier to use than the exiting teleport to any portal method, since we don’t have to scroll half-way around the world to the destination. We pay the TC when we make it rather than each time we use it, although I’d be willing to pay a small amount per use as well, which might end up being more expensive in the long run. (It will sneak up on us, like my phone data usage.)
Limiting it to four pairs keeps it balanced.