All stars are connected by default. And there isn't any way to change it. Sorry.

There aren't any visible lanes between stars. I suppose you could make lanes between planets invisible, and just link every planet to every other planet

I think what he's asking is how to put in a star in the distance (for visual effect maybe?) But disable the phase lane linking the main game solar systems star and distant star so people can't travel there.

Thanks folks for all your responses. To be honest, I'm trying to cheat a bit here because the map I am playing has 5 phaselanes from my home star to local planets/asteroids and I can't defend all those connections and put together a fleet capable of attacking the remaining planets in the system.

So, I thought if I could temporarily remove the stellar phaselanes so no more bad guys would come through the back door, I could redeploy those defensive ships into the battle for the remaining planets.

Dreyfuss, your idea seems like a good way to achieve this, I'll give it a try.