Question Assigning a random scoreboard objective to a player and no one else

I've set this up so certain roles are added to the scoreboard and I'd like to make it so each player gets a random role and no one else would have that same role. How would I go about doing that?

Code:

package com.CoinSlotGaming.TOS;

import org.bukkit.Bukkit;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;

public class Role {
    ScoreboardManager manager = Bukkit.getScoreboardManager();
    Scoreboard board = manager.getNewScoreboard();

    Objective objective1 = board.registerNewObjective("Sheriff", "dummy");
    Objective objective2 = board.registerNewObjective("Doctor", "dummy");
    Objective objective3 = board.registerNewObjective("Investigator", "dummy");
    Objective objective4 = board.registerNewObjective("Jailor", "dummy");
    Objective objective5 = board.registerNewObjective("Medium", "dummy");
    Objective objective6 = board.registerNewObjective("GF", "dummy");
    Objective objective7 = board.registerNewObjective("Framer", "dummy");
    Objective objective8 = board.registerNewObjective("Exe", "dummy");
    Objective objective9 = board.registerNewObjective("Escort", "dummy");
    Objective objective10 = board.registerNewObjective("Mafioso", "dummy");
    Objective objective11 = board.registerNewObjective("Lookout", "dummy");
    Objective objective12 = board.registerNewObjective("SK", "dummy");
    Objective objective13 = board.registerNewObjective("Vig", "dummy");
    Objective objective14 = board.registerNewObjective("Jest", "dummy");
    Objective objective15 = board.registerNewObjective("Retrib", "dummy");
   
}