Looking at the five, they all had training attire on.
Brutus wore light armor, the age and luster of his equipment pretty glaring to an observant eye. Justin and Clark wore similar-looking armor, with the former's looking a lot lighter, while the latter had more bulk to it.
Belle and Lucielle had some Enchanted Items on them, and Belle still had a book in her hand, which made it clear they were most likely practicing Spells. While Belle had the attire similar to a student, Lucielle wore a Mage's cape,with her inner attire being a loose white shirt and long trousers.
Based on everything about their appearance, coupled with the slight looks of exhaustion on the faces of the three Otherworlders, it was easy to deduce that they were just finished with training.
Justin and Clark were with Brutus, while Belle was with Lucielle. They rendezvoused and decided to visit Alicia's room together.