[VonLeeuwen]

Untested!

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
  new cmd[128], idx;
    cmd = strtok(cmdtext, idx);
    if(strcmp(cmd,"/r",true) == 0)
    {
        new str[128], pName[MAX_PLAYER_NAME];
        GetPlayerName(playerid,pName,sizeof(pName));
        format(str,sizeof(str) , "[Radio] (%s): %s",pName, cmdtext [ 3 ] );
        for(new loopplayers = 0; loopplayers<MAX_PLAYERS; loopplayers ++)
        {
            if(IsPlayerConnected(loopplayers))
            {
                if (GetPlayerColor(playerid) == GetPlayerColor(loopplayers))
                {
                    SendClientMessage(loopplayers,0xFF0000AA,str); // red
                }
            }
        }
        return 1;
    }
    return 1;
}

Be sure you use SetPlayerColor, else this wont work!
Also, be sure to define Strtok.