How do I create a relay network for Graph Theory?

What does the 'graph theory' achievement mean by a 'relay network'? I don't see a way to connect more than two planets to one relay. But I tried connecting eight planets via relays between them and didn't get the achievement.

Over a year later I looked into this again and found my answer here:

https://steamcommunity.com/app/1264280/discussions/0/3469487...


"Then you have to build at least 6 Slip Relays which are connected to each other and connected to 8 planets. Cant remember if the planets have to trade goods."