public OnPlayerText(playerid, text[])
{
    new strName[MAX_PLAYER_NAME], strOut[129];

    GetPlayerName(playerid, strName, sizeof(strName));
    if(text[0] == ',') // he used ' ! ' before text in chat box ( change as you wish )
    {
        new string[129];
        strmid(string, text, 1, strlen(text), 129);
        if(gTeam[playerid] == TEAM_PAKISTAN || gTeam[playerid] == TEAM_GERMANY || gTeam[playerid] == TEAM_USA || gTeam[playerid] == TEAM_RUSSIA || gTeam[playerid] == TEAM_INDIA)
        {
            format(strOut, 129, "[Team Radio] %s: %s", strName, string);

            for(new i = 0; i < MAX_PLAYERS; i++)
            {
                if(gTeam[i] == gTeam[playerid]) // change this if you're not using gTeam
                    SendClientMessage(i, 0x00FF00FF, strOut);
            }
        }
        return 0; // prevent the message to be sent on global chat
    }
    return 1;
}

public OnPlayerText(playerid, text[])
{
    if(text[0] == ',') // : can be changed to whatever symbol u wanna use for player to enable the teamchat.
    {
        new string[128];  GetPlayerName(playerid, string, sizeof(string)); // Making the new's
        format(string, sizeof(string), "[Team Radio] %s: %s", string, text[1]); // Formatted the message
        printf("%s", string); // Printed it BOTH ingame + the server log

        for(new i = 0; i < MAX_PLAYERS; i++) // Getting the player team and color, required for formatting the msg.
        {
            if(IsPlayerConnected(i) && GetPlayerTeam(i) == GetPlayerTeam(playerid)) SendClientMessage(i, GetPlayerColor(playerid), string);
        }
        return 0;
    }