[FaLLenGirL]

Frist way: (here the messages will not mix each others and can't be repeated more than 1 time at 3 minutes)

PHP код:

new
    TEXT_STEP,
    TD_AGAIN_X,
    TD_AGAIN,
    Text:your_TD[ MAX_PLAYERS ]
;
public OnGameModeInit( )
{
    TD_AGAIN_X = SetTimer( "TDAgainX", 60 * 3, true );
    return 1;
}
public OnPlayrSpawn( playerid )
{
    TextDrawShowForPlayer( playerid, your_TD[ playerid ] );
    return 1;
}
stock RandomTextDraw( )
{
    foreach(new i: Player)
    {
        if( TEXT_STEP == 1 )
        {
            TextDrawSetString( your_TD[ i ], "Your first message here" );
        }
        if( TEXT_STEP == 0 )
        {
            TextDrawSetString( your_TD[ i ], "Your second message here" );
        }
        TextDrawShowForPlayer( playerid, your_TD[ i ] );
    }
    return 1;
}
function TDAgainX( )
{
    TEXT_STEP = 1;
    RandomTextDraw( );
    KillTimer( TD_AGAIN_X );
    TD_AGAIN = SetTimer( "TDAgain", 60 * 3, true );
}
function TDAgain( )
{
    TEXT_STEP = 0;
    RandomTextDraw( );
    KillTimer( TD_AGAIN );
    TD_AGAIN_X = SetTimer( "TDAgainX", 60 * 3, true );
} 


Another way: (here one message can be repeated more than 1 time at 3 minutes)

PHP код:

new Text:your_TD[ MAX_PLAYERS ];
new RandomTextdraw[ ][ ] =
{
    "Your first message",
    "Your second message"
};
public OnGameModeInit( )
{
    SetTimer( "RandomTextDrawTimer", 60 * 3, 1 );
    return 1;
}
public OnPlayrSpawn( playerid )
{
    TextDrawShowForPlayer( playerid, your_TD[ playerid ] );
    return 1;
}
function RandomTextDrawTimer( )
{
    foreach(new i: Player)
    {
        TextDrawSetString( your_TD[ i ], RandomTextdraw[ random( sizeof( RandomTextdraw ) ) ] );
    }
    return 1;
} 


I literally think that you will use the first way that i gave you here.
I don't think that you want messages to repeat. So use first. It is ofc your choice.