Booking flights for 7 adults under one ticket....any tips?

It is myself, my boyfriend, my son and his four friends (all 18+) going on a trip and I want all of our tickets to be grouped together in case something goes wrong. But I'm noticing that I can't book more than 6 tickets at once on any platform - Expedia, United, ANA, Chase Travel, etc. Everyone needs me to call to book the tickets.

Is this normal? Are the tickets going to be more expensive since I'm calling?? Are there any tricks or tips from people who have done this before?? Or is it just the same as online, just by phone this time?