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In a future where monogamy is considered an aberration, poor Murray deals with his feelings of exclusivity for Kay. The Group is a set of twelve people who engage in a kind of virtual sex: one couple has intercourse while wired to machines, and the rest experience it vicariously wherever they are in the world. Fairly explicit, but not down-and-dirty. There's also some unexplained kind of teleportation in this medium-future setting.
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