We are a family or group of friends traveling together. Can we book appointments at the consulate for all of them on the same day at the same time?

No.

As the consulates are very busy, it will be difficult to make appointments for everyone on the same day or at the same time. Most likely you should be open to applying at different applicable consulates on different dates to make sure you get visas on time for your trip. We suggest you plan in advance to avoid any issues.