Is it possible to make unions/parts/meshes weld onto your head if in a group?

I have this script which basically puts the hat on your head, I'm wondering if it's possible to make it put it on your head when the player spawns and if your able to do it so it gives it depending on rank?

local hat = script.Parent
hat.PrimaryPart = hat:WaitForChild("Head") normal Head.

function weldParts(part0, part1) 
	local newWeld = Instance.new("Weld")
	newWeld.Part0  = part0
	newWeld.Part1  = part1
	newWeld.C0     = CFrame.new()
	newWeld.C1     = part1.CFrame:toObjectSpace(part0.CFrame)
	newWeld.Parent = part0
end

hat.Head.Touched:connect(function(hit)
	if hit.Parent:FindFirstChild("Humanoid")  and not hit.Parent:FindFirstChild("Earl's Coronet")then else return end
	for _, v in pairs (hit.Parent:GetChildren()) do 
		if v:IsA("Hat") then
			v:Destroy()
		end
	end
	local head = hit.Parent:FindFirstChild("Head")
	local newHat = hat:Clone()
	newHat:FindFirstChild("HatScript"):Destroy()
	newHat:SetPrimaryPartCFrame(head.CFrame) 
	newHat.PrimaryPart:Destroy()
	for _, part in pairs (newHat:GetChildren()) do
		if part:IsA("BasePart") then
			weldParts(head, part)
			part.CanCollide = false
			part.Anchored = false
		end
	end
	newHat.Parent = hit.Parent
end)

Um try this?

Create a normal script inside serverscriptserver and put in:

local GroupId = GROUPIDHERE

game.Players.PlayerAdded:Connect(function(plr)
	if plr:IsInGroup(GroupId) then
		Instance.new("BoolValue",plr).Name = "IsInGroup"
		local Rank = Instance.new("StringValue")
		Rank.Name = "GroupRank"
		Rank.Value = plr:GetRankInGroup(GroupId)
		Rank.Parent = plr
	end
end)

then edit your code with:

local hat = script.Parent
hat.PrimaryPart = hat:WaitForChild("Head") normal Head.

function weldParts(part0, part1) 
    local newWeld = Instance.new("Weld")
    newWeld.Part0  = part0
    newWeld.Part1  = part1
    newWeld.C0     = CFrame.new()
    newWeld.C1     = part1.CFrame:toObjectSpace(part0.CFrame)
    newWeld.Parent = part0
end

hat.Head.Touched:connect(function(hit)
    if hit.Parent:FindFirstChild("Humanoid")  and not hit.Parent:FindFirstChild("Earl's Coronet")then else return end
if game.Players[hit.Parent.Name]:FindFirstChild("IsInGroup") and game.Players[hit.Parent.Name]:FindFirstChild("GroupRank").Value >= PUTRANKNUMBERHERE then
    for _, v in pairs (hit.Parent:GetChildren()) do 
        if v:IsA("Hat") then
            v:Destroy()
        end
    end
    local head = hit.Parent:FindFirstChild("Head")
    local newHat = hat:Clone()
    newHat:FindFirstChild("HatScript"):Destroy()
    newHat:SetPrimaryPartCFrame(head.CFrame) 
    newHat.PrimaryPart:Destroy()
    for _, part in pairs (newHat:GetChildren()) do
        if part:IsA("BasePart") then
            weldParts(head, part)
            part.CanCollide = false
            part.Anchored = false
        end
    end
    newHat.Parent = hit.Parent
end
end)