Hi. The answer would be Bluetooth or, for iOS devices, Airplay. I say "would be" because from your profile you appear to have only older Sonos speakers, which lack these options 

Your could add a Sonos Roam to your set up, then group your other speakers to it.

Are the tracks also held on a PC? If so then you could create a Sonos Music Library and control play using the.Sonos phone app.

Upload them to iBroadcast.com and add that service to your Sonos system.