How can I put the Param's FilterDescendantsInstance as variable?

How can I put the Param’s FilterDescendantsInstance as variable?

wait(3)
local Character = game.Players.LocalPlayer.Character
local Camera = workspace.Camera

local params = RaycastParams.new()
params.FilterType = Enum.RaycastFilterType.Whitelist 
params.FilterDescendantsInstances = {workspace.Model.Parto} 

game:GetService("RunService").RenderStepped:Connect(function() 
	local cameraPos = Camera.CFrame.Position  
	local characterPos = Character:GetPrimaryPartCFrame().Position 
	local raycastResult = workspace:Raycast(cameraPos, (characterPos - cameraPos), params)
	if raycastResult then 
		workspace.Model.Parto.Transparency = 0.6
	else
		workspace.Model.Parto.Transparency =  0
	end
end)

I am trying to make multiple parts at once and when the player is behind through the listed whitelisted walls, it will make the wall transparent. But I can only store one part per one script. How can I make it store multiple part at one script?

Probably would do it like this:

local filter = {workspace.Model.Parto}
-- then update the filter as needed, you can add more parts by simply inserting:
table.insert(filter, workspace.OtherPart)
-- however, I'm pretty sure you need to update the RaycastParams every time you cast the ray/insert to the table as the table isn't mutable:
params.FilterDescendantsInstances = filter
workspace:Raycast(cameraPos, direction, params)