#include <YSI\y_groups>
#include <YSI\y_classes>
#include <YSI\y_commands>

new
    Group:gGroupPolice,
    Group:gGroupCivilian,
    Group:gGroupCanBePolice;

public OnGameModeInit()
{
    // Create the groups.
    gGroupPolice = Group_Create("Police");
    gGroupCivilian = Group_Create("Civilian");
    gGroupCanBePolice = Group_Create("Off Duty");
    
    // Create the police skins for class selection.
    // Note that "Class_Add" and "Class_AddForGroup" can have up to 13 optional
    // weapons with ammo, including "WEAPON_ARMOUR" with armour amount.
    Class_AddForGroup(gGroupPolice, POLICE_SKIN, X, Y, Z, A, WEAPONS);
    // More go here.
    
    // Create the civilian skins.
    Class_AddForGroup(gGroupCivilian, CIVILIAN_SKIN, X, Y, Z, A, WEAPONS);
    // More go here.
    
    // Set the "/duty" command to only be used by people who can be police.
    // First disable the command for all players.
    Group_SetGlobalCommand(YCMD:duty, false);
    // Secondly enable it only for people in the group who can be police.
    Group_SetCommand(gGroupCanBePolice, YCMD:duty, true);
}

public OnPlayerLogin(playerid)
{
    // Or equivalent callback/code in your mode.
    // Set any players who CAN be police in to the "can be police" group.
    if (/* your code for can be police */)
    {
        Group_SetPlayer(gGroupCanBePolice, playerid, true);
    }
}

public OnPlayerConnect(playerid)
{
    // Add all players to the civilian group by default.
    Group_SetPlayer(gGroupCivilian, playerid, true);
}

YCMD:duty(playerid, params[], help)
{
    if (help)
    {
        // Display the help on this command.
        return SendClientMessage(playerid, 0xFF0000AA, "Allows a player to go on duty as a member of the police");
    }
    // You can use 
    
    // Remove the player from the civilian group (as they're no longer a
    // civilian, so can't use those skins).
    Group_SetPlayer(gGroupCivilian, playerid, false);
    
    // Add the player as an on-duty police officer.
    Group_SetPlayer(gGroupPolice, playerid, true);
    
    // Instantly return the player to class selection to choose a new skin.  Now
    // that they have changed groups they will have a different selection of
    // skins available for them to choose.
    Class_ReturnToSelection(playerid);
}