Search the Sky has some similar elements to it, but isn't quite it.
Are you sure?
It's got the
bathroom attendants who are secretly the intelligentsia in it.
Extract:-
The
attendant materialized and offered Ross a towel.
"Dime?" he said wearily.
Ross fished absently in his pocket. "The thing that bothers me, Doc," he said, "is that I know there are intelligent people somewhere around. I even know what they're doing, I bet."
"They're doing exactly what I tried to do: acted as stupid as anybody else, or stupider. I'd make a guess," he said, warming up, "that if we could just make a statistical analysis of the whole planet and find the absolute stupidest-seeming people of the lot, we'd——"
He ran out of breath all at once. His eyes bulged.
He looked at the
men's-room attendant, and at the ten-cent piece in his own hand.
"You!" he breathed.
The
attendant's face suddenly seemed to come to life. In a voice that was abruptly richer and deeper than before, the man said: "Yes. You had to find us yourself, you know"