Assalaamu alaykum wa rahmatullaahi wa barakaatuhu, Shaykh. Is it from the Sunnah to say the 'Salaam' thrice when saying it to a group of people? I am asking because of the following hadith:
Anas, may Allaah be pleased with him, reported, “Whenever the Prophet, sallallaahu 'alayhi wa sallam, said something, he would repeat his words thrice so that the meaning would be fully understood, and whenever he came upon a group of people, he would greet them, and he would repeat his salutation thrice.” [Al-Bukhari and Muslim (*hadith is not found in Muslim, editor)]
May Allaah reward you, Shaykh.

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

First of all, the hadeeth which you inquired about was reported by Al-Bukhari in his Saheeh, and it is not in Saheeh Muslim.

This hadeeth indicates that when the Prophet greeted the people with Salam, he used to do so three times.

Ibn Al-Qayyim clarified the guidance of the Prophet in the matter in Zaad Al-Ma’aad, as he said:

“It was his guidance to say the Salam thrice, as is related in Saheeh Al-Bukhari from Anas : 'When the Messenger of Allah said something, he would repeat it thrice so that the meaning would be fully understood, and when he came upon a group of people and greeted them, he would greet them thrice.' Perhaps this was his guidance in greeting the large group of people for whom one greeting would not suffice to reach them all or maybe he did so to ensure that they all heard it when he thought that they did not hear the first greeting. Indeed, when he reached the house of Sa’d ibn ‘Ubadah, he greeted three times, and when no one answered him, he left. Otherwise, if his guidance had been to always greet three times, then his Companions would have greeted him in the same manner, and he would have greeted everyone whom he met three times, and when he entered his house, he would have also greeted them three times. However, if someone looks at his guidance, he will see that this was not the case and that he only repeated the Salam occasionally, when needed.”

Allah knows best.