How to auto assign request to queue depending on domain name

Queues are based on filters.  You don't really "assign to a queue", you have the request have data that the queue selects for.

In this case, you will need something that can look at the incoming email address, and work out how to get a queue to filter on it.  When I've done this before, it's been a script to pull the domain out of the email as a field, or work out the reporter's domain and add it to the issue so the queues can filter on it (and I've only done it on Server)