[Jstylezzz]

It's exactly the same idea, it would look like this:

pawn Код:

if(!strcmp(cmdtext, "/members")) 
    {
    if(Gangvar[playerid] == 0) return SendClientMessage(playerid,-1,"You're not in any gang");//preventing the player from doing the command if he/she is not in a gang
    new string[128],pName[MAX_PLAYER_NAME];//declare the string which we're going to format a little later, aswell as the name string
    SendClientMessage(playerid,-1,"Current members online in your gang:");
    for(new i=0; i < MAX_PLAYERS; i++)//here we loop trough all players online at the moment
    {
        if(Gangvar[i] == Gangvar[playerid])//if the player is in the same gang as the command executer, continue
        {
        GetPlayerName(i,pName,MAX_PLAYER_NAME);//format the name string with the member's name
        format(string,sizeof(string),"* %s",pName);//format the string with the name of the online member
        SendClientMessage(playerid,-1,string);//send the formatted string to the player
        }
    }
    return 1;//to let the script know this was a valid command
}

It's recommended that you upgrade to ZCMD or y_cmd by the way.

EDIT: I'm not sure how your system works, but I think you need to replace the Gangvar with the var you use for your enum (I can't be sure since I don't know how you use it).
((Remember, don't double post!))

Personally I wouldn't create a new enum to identify the gangs, I would just add pGang or something in the player enum, because it's easier to loop trough that, using only PlayerEnum[playerid][Gang] == 1, like so.