I would consider the context to get the correct formal register.

For an event with people of equal station and no elevation of class - “Hello everybody, how are we all tonight?”

For closer friends a simple greeting works best - “Friends! May I have your attention?”

If you are in a close group of Australians - “Oi cunts! Shut up for a sec!”

And if you are in a group including any billionaires just sharpen the guillotine and don’t give them any warning.