How do I make math.random randomize more than once?

My script is randomizing the CommonBelts once so if in the table Common is chosen twice, both the Commons will be exactly the same Common. And if all four in the table are Commons all four of them will be the same. The same thing is happening for the other rarities too. Please help.

math.randomseed(tick())
local Common = CommonBelts[math.random(#CommonBelts)]
local Uncommon = UncommonBelts[math.random(#UncommonBelts)]
local Rare = RareBelts[math.random(#RareBelts)]
local Legendary = LegendaryBelts[math.random(#LegendaryBelts)]
local BeltRarities = {} --A long list that includes Common, Uncommon, Rare, and Legendary.
local Belts = {BeltRarities[math.random(#BeltRarities)],BeltRarities[math.random(#BeltRarities)],BeltRarities[math.random(#BeltRarities)],BeltRarities[math.random(#BeltRarities)]}