This is already a request here, maybe add your vote to this one:
https://alexa.uservoice.com/forums/906892-alexa-skills-developer-voice-and-vote/suggestions/33800590-bring-multi-room-support-to-audioplayer-api-stream

I got my Alexa devices today and I'm surprised such a basic feature is not available. I have connected speakers but I can't play my own music to these connected speakers? Old systems much less sophisticated than Alexa can do this. I actually think about sending the devices back, as having my audio playing in multiple rooms was a main reason for buying a set of connected speakers.

How is this not a thing? The functionality exists in the product already, just let skills access it. (facepalm)

This is the one thing that holds me back from fully relying on Echo's for music for our house. We have a lot of locally stored music that is from bands that will never be on Amazon's music services, and would like to play them throughout the house.

ABSOLUTELY NEEDED. Having to create a preferred speaker is a hokey workaround for what is otherwise a great skill.

Amazon please, please, please support this suggestion and extend support for 3rd party apps. I use a 3rd party streaming service in my home in order to access an extensive library of high quality audio, most of which is unavailable on streaming services, and never using sufficient quality. Your users (Amzon users that is!!!) both need and deserve this consideration.

Ian Telford (Amazon Prime, multiple Alexa Echo, Firestick, and more)

I would like to play "my music" which I have accumulated and saved over many years. I could join prime but that has two caveats: I have more access but the data base includes music I have no interest in. Even this expanded data base does not include all the music I have saved. My MEDEA needs to add other music data bases besides AMAZON so that I may perhaps play "my music". Adding multi-room capability provides convenience by not forcing me to carry my TAP device around with me to each room, by not forcing me to sit in front of my PC and by allowing listening on better quality speaker devices.

Please add this functionality for 3rd party skills. Your Echo owners are being left behind compared to other more sophisticated competitors. We have 7 of them, but I can link up my (older) Sonos devices more flexibly ... and on the fly.

Please add it as specified

Please add support for multiroom audio as described in the post.

+1

BBC, MyMedia please allow them to support multi room

Multi-room support for Alexa's AudioPlayer API would be a HUGE feature for us!

Please add multi room support for 3rd party applications. I want to be able to use MyMedia seamlessly.

I have invested in 6 Echo devices in my home and this would be something that would be an addition that would make the majority of Amazon Customers very pleased with.

It's a must!

Please can you add mulit room streaming for 3rd party API's, you know it's the right thing to do.

This is beyond essential

I hope Alexa multiroom API support is added so My Media can use it.

Please add multi room support for 3rd party applications

Pleeease! add multi-room functionality to allow Alexa to strut her stuff!