Because of the way plantuml works (as far as I know), I have the following
code:
@startuml

[Producer 1\nProducer 2\nProducer ...\nProducer n] as Producers

cloud {
  [Internet] as Internet1
}

node RabbitMQ #LightSteelBlue {
  [Exchange]
  [Queue 1\nQueue 2\nQueue ...\nQueue n] as Queues
}

cloud {
  [Internet] as Internet2
}

[Consumer 1\nConsumer 2\nConsumer ...\nConsumer n] as Consumers


[Producers] -> [Internet1]  : Publish
[Internet1] -> [Exchange]   : Publish
[Exchange]  -> [Queues]     : Route
[Queues]    -> [Internet2]  : Consume
[Internet2] -> [Consumers]  : Consume

@enduml

Which gives the attached graphic.

The problem is that there are four producers, queues and consumers. Is it
possible to put three lines in the components to signify that?

-- 
Cecil Westerhof