keep track of a certain ammount of messages, then just put all the messages together to make 1 hud. then after a time period, take away a message.
heres some pseudo code(i think).
player sends a message, message is saved into array[0][]
another player sends a message, message is saved into array[1][]
print array[0]+array[1].
after X seconds, array[0] should be overwritten by array[1] and array[1] should be filled with nothing
print array[0]+array[1]
that should give you a message like hud system. (it made sense in my mind, sorry if it doesn't in yours)