[quote=Skallagrim]
LOL Gado you always crack me up. 
[/quote]

[quote] There are two portals on each planet both of them are hidden and their locations forgotten in the hoary past. One portal leads to the Nexus, the other leads to one other planet. Each planet therefore is a terminus for one planet's gate and access one other planet's gate, and no this is not a two way street, each portal is one way. Only the Nexus allows access to all planets both to the planet and returning to the Nexus.[/quote]

And then there's some that closed/opened or changed destination of its gate periodically.
....Wait, each portal is one way?