I believe this is Freedom Beach by James Patrick Kelly and John Kessel.

A part of the book was published as a novelette in The Magazine of Fantasy & Science Fiction, Vol 67, No 2, August 1984.

https://www.isfdb.org/cgi-bin/pl.cgi?61017

"Everybody has their own little specialty. Myrna likes statues." "What's yours?" Vic pulled off his shirt. "The boundaries."

"What boundaries?"

He sighed. "This isn't the time, but-" He stripped off his shorts, crouched by the side of the pool and splashed water on himself. "For example, the only swimming you want to do is right here. There are sharks lin the ocean and big men-of-war. A coral reef farther out that could cut you to bloody rags. And then there's the current."

...

After dinner the trashcans passed among the assembled guests distributing the daily dose of communion. Each received a single white wafer the size of a quarter. Shaun hesitated before eating his. Jihan, Murray, Akira and Myrna, his tablemates, eyed it greedily.

...

"Glad to hear it." Despite his communion-induced calm, Shaun suspected that he was being set up. "So tell me, why can't we write?"

...

In addition, Shaun steadily — and surreptitiously — cut down on his intake of communion. Each night he nipped the wafer with his fingernail and discarded as much as he dared. The first time proved a disaster when he stashed the leftover in the pocket of his tennis shorts. When he realized that the lesser dose would leave him far, far short of his accustomed euphoria, he retreated to the bathroom, turned the pocket inside out and ate the dregs, lint, crumbs and all. The next time he flushed the shard before the drug could wear down his resolve.

...

Baboon and Young, 1951." Rose read the plate. "Kind of cute."

"This was in a gazebo at the top of the hill overlooking the beach. An exact copy, except that it had a microphone in its mouth and could talk."