How to set homologation restrictions in private lobby?

This has probably been asked before, but my Google-fu seems to be failing me.

My friends and I have recently come from FH4 to FM7 looking for a more realistic driving experience. And last night we were trying to see how private multiplayer lobbies work and the one thing I just couldn’t figure out is how to set the homologation restrictions.

I had set the lobby to B-class and Sport Compacts, so I could race with my B519 Tamo Racemo. Then my friends load in, pick a car and press the “automatic homologation” button and they all get B600 cars. Which seems odd because in Single Player whenever i want to race with my Tamo Racemo, the game will complain at me that I have to stick to B520 or below.

So I am wondering how can I enforce this B520 homologation in a private lobby? Same goes for any division really. I like the homologation mechanic, especially because it seems much more varied than it is in FH4, but what good is it when it doesn’t seem to apply in multiplayer?