The only way it is possible in 1 trigger is if all the players are checked in the players screen of the trigger. Otherwise, you will have to use a switch, score, unit, resource, etc. to handle the conditions. Depending on the conditions and other actions, it may be easier to simply use 2 triggers each.
For player activating triggers, set switch.
For all players, if switch is set, display text, disable switch.
If it is all combined and linked together, you can just set a switch to activate them all. If not, I may suggest setting an unused score amount (I love doing this, so long I don't lose track of what I use) to a number. For example, set razing or custom score to 44, and it displays the 44th message.
Just some ideas. Sucks that you can only display message for "current player," doesn't it.
EDIT: Forget the score idea, death counters is a lot better of an idea. Same basic idea, though. Go moose

EDIT#2: The example I gave above with switches is a bad one, because the first player MAY disable the switch before everyone else has a chance to see the message.
I would personally just set a death counter of 1 unit to a # between 1 and 288 for all players, and then make 288 triggers to reset the death counter to 0 and display each corresponding message.