Yup probably family. I was only making a joke because on most identifying things like on a locker it's usually only First letter of first name followed by full last name.
ie. John Doe & Jack Doe = J. Doe
Looking at the two on the right. I hope they don't have the same first letter in their first name. It could be quite confusing around the firehouse if they did! 🤣 🤣🤣