Playing music from mac mini music library through hifi

I have my whole music library stored upon my mac mini. I would like to be able to connect this to a hifi/amplifier with wireless satellite speakers around my home to be able to access and play music where and when I want to. An intelligent system with voice recognition (ala Amazon Alexa ) would be preferable.
Could anyone tell me how I could do this please and what kit I would need. Thanks.

In it's current state, using any of the assistants available off the shelf what you're asking isn't possible.

None of them can currently index and pull from your local network.

However, if you were to upload your collection to Amazons Music service or Google Play then Alexa and Google Home will allow you to play your tracks from the service (providing the service recognises the track/artist etc). Both Google Home and Alexa devices have a multi room concept. Alexa can sync between echo devices or can push to one or more sonos devices. Google Home can sync between google home devices and chromecasts. If you already have a multi room amp/speaker setup you can just have a single assistant linked in.

So obviously these will stream back to your home so will require a web connection and, depending on the number of tracks uploaded you may need to pay for the service.

I can't see the the current generation 'smart' devices to support exactly what you want:
a) these companies exist by selling services
b) they use cloud machine learning to deliver these services and you wouldn't particularly want these device hunting around your local network

Bose multi room speakers might be what you need. Not cheap though.
https://www.bose.co.uk/en_gb/products/speakers/multi_room_speakers.html