Rabbitmq requeue/queue with custom timeout

Question

For reasons I can't use the delayed plugin. So I've made implemention with dead-letter-exchange.

The thing is that my letters have different timeouts. Here comes the main problem: first letter with timeout 15s blocks letter with 1s timeout. Is there a way to get around this FIFO pattern?

Here are approaches that didn't work.

1. I dunno what the actual timeout would be, so I can't really pre-create n queues with static timeouts and throw letters there.

2. There won't be a lot of letters, so i thought i can declare a queue for each request with custom timeout and delete it when it's no more needed. In this case I need to delete this queue in some time if no more letter are published. And I don't think I am able to do this.

I've read about NServiceBus approach for delayed messaging, but there is not much info on how to implement this.