Cartel was the word that came to my mind as well. Any kind of exa-corporate relationship between companies leads to a cartel type situation. It doesn’t have to

Cartel was the word that came to my mind as well. Any kind of exa-corporate relationship between companies leads to a cartel type situation. It doesn’t have to be about coordinating prices for services either. It could be as little as companies prefer to do business with a cartel member so as to open up opportunities with other members.