This is best adressed by abandoning the Studio 54 bouncer technique of "are you sool enough", and employing the back stage roady technique of "Sorry, you're just not on the list...but how big are your tits?".
Say it's by invite only. Or be specific; "look man, we've had alot of problems with people trashing our lot and doing stupid shit here. You're only getting in if you're invited or some one vouches for you. It's not my descision."
Because of that last option, keep yourselves up agains the building and away fromt he road. I can imagine people creeping down the street yelling up at the group; "HEY SAM! HEY, ITS ME, LEEROY, WE MET THAT ONE TIME BACK AT THAT PLACE, TELL'M TO LET EM IN!"