In general, the person who is in charge of paying the bill will have access to all information.
Now, if you're worried about inadvertently receiving calls & text messages from someone you're sharing data with, that's probably not going to happen.
If the people you're sharing with all have iPhones, you can easily set up different Apple IDs and iCloud accounts to provide some privacy. Still, it does not keep the person in charge of paying the bill from seeing all incoming and outgoing numbers associated with calls and text messages because that information is readily available via the service provider. I hope that made sense.
Just Me, D