How to rotate character's Upper Torso without rotating the Lower Torso?

I'm trying to make it so the character's upper torso follows the player's mouse and I've gotten the angle but I just don't know how to rotate the upper torso without rotating the lower one.

Here's the code

local Player = game:GetService("Players").LocalPlayer
local Mouse = Player:GetMouse()
local Character = script.Parent

Mouse.Move:Connect(function()
	local Angle = math.asin((Mouse.Hit.p - Mouse.Origin.p).unit.y)
	-- Rotate the torso here
end)