I am not sure that this can be done simply. If you were to try this:
Hint Format["Hi %1", Player]
you would just get "Hi East:Bravo Black 1", or something like that. There may be a slick way to do this, but I do not know it. Here is a clumsy way:
You will have to create an array of names and a matching array of units.
In your init.sqs
nameArray = ["Player1","Player2","Player3",....]
unitArray = [Player1,Player2,Player3,....]
Now when your trigger is activated you will have to search the unitArray to see what element of nameArray to use.
In your trigger On Activation:
{if ((thisList select 0) == (unitArray select _i)) then {playerName = nameArray select _i} ; _i = _i + 1} forEach nameArray; hint format ["%1 activated the trigger",playerName]
Note that if the trigger is activated by more than one player, this only gives the name of one of the players.