Change origin of part in studio?

I am trying to tween these two parts, but they are rotating from the centre and not from the left/right. How do I fix this?

Video: https://streamable.com/3qg6tt

My Code:

local RS = game:GetService("ReplicatedStorage")
local TweenService = game:GetService("TweenService")
local Settings = require(RS.GateSettings)

local model = script.Parent
local trigger = model.TouchPart

local left = model.GateL
local right = model.GateR

local leftro = CFrame.Angles(0,math.rad(90),0)
local rightro = CFrame.Angles(0,math.rad(-90),0)

local fleftro = left.CFrame * leftro
local frightro = right.CFrame * rightro

local activated = false

local tweenInfo = TweenInfo.new(
    Settings.Speed,
    Enum.EasingStyle.Quart,
    Enum.EasingDirection.Out,
    0,
    true,
    0
)

local function open(otherPart)
    local player = game.Players:FindFirstChild(otherPart.Parent.Name)
    if player and not activated then
        activated = true
        local tweenL = TweenService:Create(left, tweenInfo, {CFrame = fleftro})
        local tweenR = TweenService:Create(right, tweenInfo, {CFrame = frightro})

        tweenL:Play()
        tweenR:Play()

        tweenL.Completed:Wait()

        activated = false
    end
end

trigger.Touched:Connect(open)