I will play. I would assume, since we get to insert the name of the group, that I would know whether to expect 2-4 (home invasion scenario) or 10+ (rioting or mostly peaceful demonstrations).
Handgun only: I have 2 choices depending on number of potential intruders. With a small number of intruders, I would pick up my S&W Governor. It has 6 rounds of home defense 410 bore. With a large number of intruders, I would pick up my FN FiveseveN. It has up to 30 rounds of high speed 5.7x28 that does not over penatrate.
Rifle option:. For me, there is little to discuss. I would choose my AR57. It is the same round as the FiveseveN but with a 50 round magazine. It is light and there is little recoil. Follow up shots are quick, even with a binary trigger installed. I have several options of caliber in rifles, but most would be likely to go through any and everything in the house and beyond.