how to make permanent teleporting gateways

I would like to have a custom map that has permanent teleporting gateways to each other planet that cannot be destroyed. That way everyone can send units through immediately and if you guard the chokepoint then you can prevent them from using that particular teleporting gateway.

does anyone know if this is possible to do?

I'd categorize it as poor solution likely possible.

You'll need cheats to make the gateways. At the moment this means you need to run your own server. Then you'll need to make it hard for players to abuse the cheats (this part is relatively known)

Linking them will be harder. You may need a dummy AI player so players can't turn off the gates or anything. Which means you'll need the player control cheat as well to go configure things.

You might be able ameliorate many of these issue by having a human host with a special commander that sets things up and links gates.

Gates could be made very hard to destroy. If you wanted to mod all ammos you may be able to do something with armor type. Then you have to pick between reclaimable-to-death, and making a near limitless metal source. You might have to mod the reclaim command out. Hacking with alliances may be another option, I'm not very familiar with what you can or can't do to an ally.

we need to be able to preplace units in the planet/system editor.
uber pls

Wow. Thanks for your detailed reply.